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Search Results (361539 CVEs found)

CVE Vendors Products Updated CVSS v3.1
CVE-2026-53275 1 Linux 1 Linux Kernel 2026-06-28 8.8 High
In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: Fix use-after-free when processing MLD queries When processing an MLD query, a pointer to the multicast group address is retrieved when initially parsing the packet. This pointer is later dereferenced without being reloaded despite the fact that the skb header might have been reallocated following the pskb_may_pull() calls, leading to a use-after-free [1]. Fix by copying the multicast group address when the packet is initially parsed. [1] BUG: KASAN: slab-use-after-free in __mld_query_work (net/ipv6/mcast.c:1512) Read of size 8 at addr ffff8881154b8e90 by task kworker/4:1/118 Workqueue: mld mld_query_work Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_address_description.constprop.0 (mm/kasan/report.c:378) print_report (mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:595) __mld_query_work (net/ipv6/mcast.c:1512) mld_query_work (net/ipv6/mcast.c:1563) process_one_work (kernel/workqueue.c:3314) worker_thread (kernel/workqueue.c:3397 kernel/workqueue.c:3478) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) </TASK> [...] Freed by task 118: kasan_save_stack (mm/kasan/common.c:57) kasan_save_track (mm/kasan/common.c:78) kasan_save_free_info (mm/kasan/generic.c:584) __kasan_slab_free (mm/kasan/common.c:253 mm/kasan/common.c:285) kfree (./include/linux/kasan.h:235 mm/slub.c:2689 mm/slub.c:6251 mm/slub.c:6566) pskb_expand_head (net/core/skbuff.c:2335) __pskb_pull_tail (net/core/skbuff.c:2878 (discriminator 4)) __mld_query_work (net/ipv6/mcast.c:1495 (discriminator 1)) mld_query_work (net/ipv6/mcast.c:1563) process_one_work (kernel/workqueue.c:3314) worker_thread (kernel/workqueue.c:3397 kernel/workqueue.c:3478) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
CVE-2026-53273 1 Linux 1 Linux Kernel 2026-06-28 7.8 High
In the Linux kernel, the following vulnerability has been resolved: tee: optee: prevent use-after-free when the client exits before the supplicant Commit 70b0d6b0a199 ("tee: optee: Fix supplicant wait loop") made the client wait as killable so it can be interrupted during shutdown or after a supplicant crash. This changes the original lifetime expectations: the client task can now terminate while the supplicant is still processing its request. If the client exits first it removes the request from its queue and kfree()s it, while the request ID remains in supp->idr. A subsequent lookup on the supplicant path then dereferences freed memory, leading to a use-after-free. Serialise access to the request with supp->mutex: * Hold supp->mutex in optee_supp_recv() and optee_supp_send() while looking up and touching the request. * Let optee_supp_thrd_req() notice that the client has terminated and signal optee_supp_send() accordingly. With these changes the request cannot be freed while the supplicant still has a reference, eliminating the race.
CVE-2026-53270 1 Linux 1 Linux Kernel 2026-06-28 7.8 High
In the Linux kernel, the following vulnerability has been resolved: ipvs: clear the svc scheduler ptr early on edit ip_vs_edit_service() while unbinding the old scheduler clears the svc->scheduler ptr after the scheduler module initiates RCU callbacks. This can cause packets to use the old scheduler at the time when svc->sched_data is already freed after RCU grace period. Fix it by clearing the ptr early in ip_vs_unbind_scheduler(), before the done_service method schedules any RCU callbacks. Also, if the new scheduler fails to initialize when replacing the old scheduler, try to restore the old scheduler while still returning the error code.
CVE-2026-53268 1 Linux 1 Linux Kernel 2026-06-28 8.2 High
In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack_irc: fix possible out-of-bounds read When parsing fails after we've matched the command string we should bail out instead of trying to match a different command. This helper should be deprecated, given prevalence of TLS I doubt it has any relevance in 2026.
CVE-2026-53267 1 Linux 1 Linux Kernel 2026-06-28 7.8 High
In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_ct: bail out on template ct in get eval I noticed this issue while looking at a historic syzbot report [1]. A rule like the one below is enough to trigger the bug: table ip t { chain pre { type filter hook prerouting priority raw; ct zone set 1 ct original saddr 1.2.3.4 accept } } The first expression attaches a per-cpu template ct via nft_ct_set_zone_eval() (nf_ct_tmpl_alloc -> kzalloc, tuple is all zero, nf_ct_l3num(ct) == 0). The next expression then calls nft_ct_get_eval() on the same skb, treats the template as a real ct and hits the 16-byte memcpy path. With dreg at NFT_REG32_15 this overflows past struct nft_regs on the kernel stack; with smaller dreg values it silently clobbers adjacent registers. Reject template ct at the eval entry and in nft_ct_get_fast_eval(), mirroring the check nft_ct_set_eval() already has. Additionally, bound the address copy in NFT_CT_SRC / NFT_CT_DST by priv->len instead of by nf_ct_l3num(ct): nf_ct_get_tuple() zeroes the tuple before pkt_to_tuple() fills in only the protocol-relevant leading bytes, so the trailing bytes of tuple->{src,dst}.u3.all are well-defined zero. priv->len is validated at rule load, so the copy size is now bounded by the destination register rather than by an untrusted field on the conntrack. [1]: https://syzkaller.appspot.com/bug?id=389cf09cb72926114fce90dc85a2c3231dcb647c
CVE-2026-53266 1 Linux 1 Linux Kernel 2026-06-28 8.8 High
In the Linux kernel, the following vulnerability has been resolved: netfilter: bridge: make ebt_snat ARP rewrite writable The ebtables SNAT target keeps the Ethernet source address rewrite behind skb_ensure_writable(skb, 0). This is intentional: at the bridge ebtables hooks the Ethernet header is addressed through skb_mac_header()/eth_hdr(), while skb->data points at the Ethernet payload. Asking skb_ensure_writable() for ETH_HLEN bytes would check the payload, not the Ethernet header, and would reintroduce the small packet regression fixed by commit 63137bc5882a. However, the optional ARP sender hardware address rewrite is different. It writes through skb_store_bits() at an offset relative to skb->data: skb_store_bits(skb, sizeof(struct arphdr), info->mac, ETH_ALEN) skb_header_pointer() only safely reads the ARP header; it does not make the later sender hardware address range writable. If that range is still held in a nonlinear skb fragment backed by a splice-imported file page, skb_store_bits() maps the frag page and copies the new MAC address directly into it. Ensure the ARP SHA range is writable before reading the ARP header and before calling skb_store_bits().
CVE-2026-53265 1 Linux 1 Linux Kernel 2026-06-28 7.8 High
In the Linux kernel, the following vulnerability has been resolved: dm cache policy smq: check allocation under invalidate lock commit 2d1f7b65f5de ("dm cache policy smq: fix missing locks in invalidating cache blocks") added mq->lock around the destructive part of smq_invalidate_mapping(), but left the e->allocated check outside the critical section. That leaves a check-then-act race. Two concurrent invalidators can both observe e->allocated as true before either of them takes mq->lock. The first invalidator that acquires the lock removes the entry from the queues and hash table and then calls free_entry(), which clears e->allocated and puts the entry back on the free list. The second invalidator can then acquire mq->lock and continue with the stale result of the unlocked check. This can corrupt the SMQ queues or hash table by deleting an entry that is no longer on those structures. It can also hit the allocation check in free_entry() when the same entry is freed again. Move the allocation check under mq->lock so the predicate and the destructive operations are serialized by the same lock.
CVE-2026-53264 1 Linux 1 Linux Kernel 2026-06-28 7.8 High
In the Linux kernel, the following vulnerability has been resolved: net/sched: act_api: use RCU with deferred freeing for action lifecycle When NEWTFILTER and DELFILTER are run concurrently it is possible to create a race with an associated action. Let's illustrate with CPU0 running NEWTFILTER and CPU1 running DELFILTER: 0: mutex_lock() <-- holds the idr lock 0: rcu_read_lock() 0: p = idr_find(idr, index) <-- action p is valid (RCU protects IDR) 0: mutex_unlock() <-- releases the idr lock 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held 1: idr_remove(idr, index) <-- Action removed from IDR 1: mutex_unlock() <-- mutex released allowing us to delete the action 1: tcf_action_cleanup(p); kfree(p) <-- Kfrees p immediately, no deferral 0: refcount_inc_not_zero(&p->tcfa_refcnt) <-- ouch, UAF p points to freed memory This patch fixes the race condition between NEWTFILTER and DELFILTER by adding struct rcu_head to tc_action used in the deferral and introducing a call_rcu() in the delete path to defer the final kfree(). Note: this is a revert of commit d7fb60b9cafb ("net_sched: get rid of tcfa_rcu") but also modernization/simplification to directly use kfree_rcu(). Let's illustrate the new restored code path: 0: rcu_read_lock() 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held 1: idr_remove(idr, index) 1: mutex_unlock() 1: call_rcu(&p->tcfa_rcu, tcf_action_rcu_free) <-- defer kfree after grace period 0: p = idr_find(idr, index) 0: refcount_inc_not_zero(&p->tcfa_refcnt) <-- fails, refcnt already 0 1: rcu_read_unlock() <-- release so freeing can run after grace period After CPU1 calls idr_remove(), the object is no longer reachable through the IDR. CPU0's subsequent idr_find() will return NULL, and even if it still held a stale pointer, the immediate kfree() is now deferred until after the RCU grace period, so no UAF can occur.
CVE-2026-53262 1 Linux 1 Linux Kernel 2026-06-28 7.8 High
In the Linux kernel, the following vulnerability has been resolved: l2tp: pppol2tp: hold reference to session in pppol2tp_ioctl() pppol2tp_ioctl() read sock->sk->sk_user_data directly without any locks or reference counting. If a controllable sleep was induced during copy_from_user() (e.g. via a userfaultfd page fault sleep), a concurrent socket close could trigger pppol2tp_session_close() asynchronously. This frees the l2tp_session structure via the l2tp_session_del_work workqueue. Upon resuming, the ioctl thread dereferences the stale session pointer, resulting in a Use-After-Free (UAF). Fix this by securely fetching the session reference using the RCU-safe, refcounted helper pppol2tp_sock_to_session(sk) on entry. This locks the session's refcount across the sleep. We structured the function to exit via standard err breaks, guaranteeing that l2tp_session_put() is cleanly called on all return paths to drop the reference. To preserve existing behavior we validate the session and its magic signature only for the specific L2TP commands that require it. This ensures that generic/unknown ioctls called on an unconnected socket still return -ENOIOCTLCMD and correctly fall back to generic handlers (e.g. in sock_do_ioctl()).
CVE-2026-53259 1 Linux 1 Linux Kernel 2026-06-28 7.8 High
In the Linux kernel, the following vulnerability has been resolved: ipv6: anycast: insert aca into global hash under idev->lock syzbot reported a splat [1]: a slab-use-after-free in ipv6_chk_acast_addr(), which walks the global inet6_acaddr_lst[] hash under RCU and dereferences a struct ifacaddr6 that has already been freed while still linked in the hash, so a later reader walks into a dangling node. In __ipv6_dev_ac_inc() the aca is allocated with refcount 1, then aca_get() bumps it to 2 to keep it alive across the unlocked region. It is published to idev->ac_list under idev->lock, but ipv6_add_acaddr_hash() runs after write_unlock_bh(). A concurrent teardown (ipv6_ac_destroy_dev() from addrconf_ifdown(), under RTNL) can slip into that window: CPU0 __ipv6_dev_ac_inc CPU1 ipv6_ac_destroy_dev (RTNL) ------------------------------ ------------------------------------ aca_alloc() refcnt 1 aca_get() refcnt 2 write_lock_bh(idev->lock) add aca to ac_list write_unlock_bh(idev->lock) write_lock_bh(idev->lock) pull aca off ac_list write_unlock_bh(idev->lock) ipv6_del_acaddr_hash(aca) hlist_del_init_rcu() is a no-op, aca is not in the hash yet aca_put() refcnt 2->1 ipv6_add_acaddr_hash(aca) aca now inserted into the hash aca_put() refcnt 1->0 call_rcu(aca_free_rcu) -> kfree(aca) The hash removal becomes a no-op because the insertion has not happened yet, so once CPU0 inserts and drops the last reference, the aca is freed while still linked in inet6_acaddr_lst[], and readers dereference freed memory after the slab slot is reused. This window opened once RTNL stopped serializing the join path against device teardown. Move ipv6_add_acaddr_hash() inside the idev->lock section so the ac_list and hash insertions are atomic with respect to teardown: a racing remover now either misses the aca entirely or finds it in both lists. acaddr_hash_lock is now nested under idev->lock, which is acquired in softirq context, so switch all acaddr_hash_lock sites to spin_lock_bh() to avoid the irq lock inversion reported in [2]. [1] https://syzkaller.appspot.com/bug?extid=a01df04303c131efbf3a [2] https://lore.kernel.org/netdev/6a194ef7.ba3b1513.1890b4.0000.GAE@google.com/
CVE-2026-53256 1 Linux 1 Linux Kernel 2026-06-28 8 High
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind() rfcomm_get_sock_by_channel() scans rfcomm_sk_list under the list lock, but returns the selected listener after dropping that lock without taking a reference. rfcomm_connect_ind() then locks the listener, queues a child socket on it, and may notify it after unlocking it. The buggy scenario involves two paths, with each column showing the order within that path: rfcomm_connect_ind(): listener close: 1. Find parent in 1. close() enters rfcomm_get_sock_by_channel() rfcomm_sock_release(). 2. Drop rfcomm_sk_list.lock 2. rfcomm_sock_shutdown() without pinning parent. closes the listener. 3. Call lock_sock(parent) and 3. rfcomm_sock_kill() bt_accept_enqueue(parent, unlinks and puts parent. sk, true). 4. Read parent flags and may 4. parent can be freed. call sk_state_change(). If close wins the race, parent can be freed before rfcomm_connect_ind() reaches lock_sock(), bt_accept_enqueue(), or the deferred-setup callback. Take a reference on the listener before leaving rfcomm_sk_list.lock. After lock_sock() succeeds, recheck that it is still in BT_LISTEN before queueing a child, cache the deferred-setup bit while the parent is locked, and drop the reference after the last parent use. KASAN reported a slab-use-after-free in lock_sock_nested() from rfcomm_connect_ind(), with the freeing stack going through rfcomm_sock_kill() and rfcomm_sock_release().
CVE-2026-53254 1 Linux 1 Linux Kernel 2026-06-28 8.1 High
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: validate skb length in MCC handlers The RFCOMM MCC handlers cast skb->data to protocol-specific structs without validating skb->len first. A malicious remote device can send truncated MCC frames and trigger out-of-bounds reads in these handlers. Fix this by using skb_pull_data() to validate and access the required data before dereferencing it. rfcomm_recv_rpn() requires special handling since ETSI TS 07.10 allows 1-byte RPN requests. Handle this by validating only the DLCI byte first, and validating the full struct only when len > 1.
CVE-2026-53253 1 Linux 1 Linux Kernel 2026-06-28 7.1 High
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: bnep: reject short frames before parsing A BNEP peer can send a short BNEP SDU. bnep_rx_frame() reads the packet type byte immediately and, for control packets, reads the control opcode and setup UUID-size byte before proving that those bytes are present. bnep_rx_control() also dereferences the control opcode without rejecting an empty control payload. Use skb_pull_data() for the fixed fields in bnep_rx_frame() so a NULL return gates each dereference. Split the control handler so the frame path can pass an opcode that has already been pulled, and keep the byte-buffer wrapper for extension control payloads. For BNEP_SETUP_CONN_REQ, name the UUID-size byte before pulling the setup payload. struct bnep_setup_conn_req carries destination and source service UUIDs after that byte, each uuid_size bytes, so the parser now documents that tuple explicitly instead of leaving the pull length as an opaque multiplication. Validation reproduced this kernel report: KASAN slab-out-of-bounds in bnep_rx_frame.isra.0+0x130c/0x1790 The buggy address belongs to the object at ffff88800c0f7908 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes to the right of allocated 1-byte region [ffff88800c0f7908, ffff88800c0f7909) Read of size 1 Call trace: dump_stack_lvl+0xb3/0x140 (?:?) print_address_description+0x57/0x3a0 (?:?) bnep_rx_frame+0x130c/0x1790 (net/bluetooth/bnep/core.c:306) print_report+0xb9/0x2b0 (?:?) __virt_addr_valid+0x1ba/0x3a0 (?:?) srso_alias_return_thunk+0x5/0xfbef5 (?:?) kasan_addr_to_slab+0x21/0x60 (?:?) kasan_report+0xe0/0x110 (?:?) process_one_work+0xfce/0x17e0 (kernel/workqueue.c:3200) worker_thread+0x65c/0xe40 (?:?) __kthread_parkme+0x184/0x230 (?:?) kthread+0x35e/0x470 (?:?) _raw_spin_unlock_irq+0x28/0x50 (?:?) ret_from_fork+0x586/0x870 (?:?) __switch_to+0x74f/0xdc0 (?:?) ret_from_fork_asm+0x1a/0x30 (?:?)
CVE-2026-53250 1 Linux 1 Linux Kernel 2026-06-28 7.8 High
In the Linux kernel, the following vulnerability has been resolved: xsk: cache csum_start/csum_offset to fix TOCTOU in xsk_skb_metadata() The TX metadata area resides in the UMEM buffer which is memory-mapped and concurrently writable by userspace. In xsk_skb_metadata(), csum_start and csum_offset are read from shared memory for bounds validation, then read again for skb assignment. A malicious userspace application can race to overwrite these values between the two reads, bypassing the bounds check and causing out-of-bounds memory access during checksum computation in the transmit path. Fix this by reading csum_start and csum_offset into local variables once, then using the local copies for both validation and assignment. Note that other metadata fields (flags, launch_time) and the cached csum fields may be mutually inconsistent due to concurrent userspace writes, but this is benign: the only security-critical invariant is that each field's validated value is the same one used, which local caching guarantees.
CVE-2026-53248 1 Linux 1 Linux Kernel 2026-06-28 8.8 High
In the Linux kernel, the following vulnerability has been resolved: net: airoha: Fix use-after-free in metadata dst teardown airoha_metadata_dst_free() runs metadata_dst_free() which frees the metadata_dst with kfree() immediately, bypassing the RCU grace period. In the RX path, skb_dst_set_noref() sets a non-refcounted pointer from the skb to the metadata_dst. This function requires RCU read-side protection and the dst must remain valid until all RCU readers complete. Since metadata_dst_free() calls kfree() directly, an use-after-free can occur if any skb still holds a noref pointer to the dst when the driver tears it down. Replace metadata_dst_free() with dst_release() which properly goes through the refcount path: when the refcount drops to zero, it schedules the actual free via call_rcu_hurry(), ensuring all RCU readers have completed before the memory is freed.
CVE-2026-53247 1 Linux 1 Linux Kernel 2026-06-28 9.8 Critical
In the Linux kernel, the following vulnerability has been resolved: net: ethernet: mtk_eth_soc: Fix use-after-free in metadata dst teardown mtk_free_dev() calls metadata_dst_free() which frees the metadata_dst with kfree() immediately, bypassing the RCU grace period. In the RX path, skb_dst_set_noref() sets a non-refcounted pointer from the skb to the metadata_dst. This function requires RCU read-side protection and the dst must remain valid until all RCU readers complete. Since metadata_dst_free() calls kfree() directly, a use-after-free can occur if any skb still holds a noref pointer to the dst when the driver tears it down. Replace metadata_dst_free() with dst_release() which properly goes through the refcount path: when the refcount drops to zero, it schedules the actual free via call_rcu_hurry(), ensuring all RCU readers have completed before the memory is freed.
CVE-2026-53246 1 Linux 1 Linux Kernel 2026-06-28 9.8 Critical
In the Linux kernel, the following vulnerability has been resolved: sctp: validate cached peer INIT chunk length in COOKIE_ECHO processing When a listening SCTP server processes a COOKIE_ECHO chunk, the cached peer INIT chunk embedded after the cookie is parsed and its parameters are later walked by sctp_process_init() using sctp_walk_params(). However, the chunk header length of this cached INIT chunk was not validated against the remaining buffer in the COOKIE_ECHO payload. If the length field is inflated, the parameter walk can run beyond the actual received data, leading to out-of-bounds reads and potential memory corruption during later parameter handling (e.g. STATE_COOKIE processing and kmemdup() copies). Add a bounds check in sctp_unpack_cookie() to ensure the cached INIT chunk length does not exceed the available data in the COOKIE_ECHO buffer before it is used.
CVE-2026-53244 1 Linux 1 Linux Kernel 2026-06-28 7.5 High
In the Linux kernel, the following vulnerability has been resolved: VFS: fix possible failure to unlock in nfsd4_create_file() atomic_create() in fs/namei.c drops the reference to the dentry when it returns an error. This behaviour was imported into dentry_create() so that it will drop the reference if an error is returned from atomic_create(), though not if vfs_create() returns an error (in the case where ->atomic_create is not supported). The caller - nfsd4_create_file() - is made aware of this by checking path->dentry, which will either be a counted reference to a dentry, or an error pointer. However the change to use start_creating()/end_creating() (which landed shortly before the dentry_create() change landed, though was likely developed around the same time) means that nfsd4_create_file() *needs* a valid dentry so that it can unlock the parent. The net result is that if NFSD exports a filesystem which uses ->atomic_create, and if a call to ->atomic_create returns an error, then nfsd4_create_file() will pass an error pointer to end_creating() and the parent will not be unlocked. Fix this by changing dentry_create() to make sure path->dentry is always a valid dentry, never an error-pointer. The actual error is already returned a different way. Note that if ->atomic_create() returns a different dentry (which may not be possible in practice) we are guaranteed (because it is only ever provided by d_spliace_alias()) that it will have the same d_parent and so it will have the same effect when passed to end_creating().
CVE-2026-53242 1 Linux 1 Linux Kernel 2026-06-28 7.8 High
In the Linux kernel, the following vulnerability has been resolved: ALSA: PCM: Fix wait queue list corruption in snd_pcm_drain() on linked streams snd_pcm_drain() uses init_waitqueue_entry which does not clear entry.prev/next, and add_wait_queue with a conditional remove_wait_queue that is skipped when to_check is no longer in the group after concurrent UNLINK. The orphaned wait entry remains on the unlinked substream sleep queue. On the next drain iteration, add_wait_queue adds the entry to a new queue while still linked on the old one, corrupting both lists. A subsequent wake_up dereferences NULL at the func pointer (mapped from the spinlock at offset 0 of the misinterpreted wait_queue_head_t), causing a kernel panic. Replace init_waitqueue_entry/add_wait_queue/conditional remove_wait_queue with init_wait_entry/prepare_to_wait/ finish_wait. init_wait_entry clears prev/next via INIT_LIST_HEAD on each iteration and sets autoremove_wake_function which auto-removes the entry on wake-up. finish_wait safely handles both the already-removed and still-queued cases.
CVE-2026-53240 1 Linux 1 Linux Kernel 2026-06-28 8.8 High
In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: fix use-after-free on first_skb in __input_process_payload __input_process_payload() stores first_skb into xtfs->ra_newskb under drop_lock when starting partial reassembly, then unlocks and breaks out of the processing loop. The post-loop check reads xtfs->ra_newskb without the lock to decide whether first_skb is still owned: if (first_skb && first_iplen && !defer && first_skb != xtfs->ra_newskb) Between spin_unlock and this read, a concurrent CPU running iptfs_reassem_cont() (or the drop_timer hrtimer) can complete reassembly, NULL xtfs->ra_newskb, and free the skb. The check then evaluates first_skb != NULL as true, and pskb_trim/ip_summed/consume_skb operate on the freed skb — a use-after-free in skbuff_head_cache. Replace the unlocked read with a local bool that records whether first_skb was handed to the reassembly state in the current call. The flag is set after the existing spin_unlock, before the break, using the pointer equality that is stable at that point (first_skb == skb iff first_skb was stored in ra_newskb).