The missing check allows an unprivileged local user who knows or can guess a target's process and thread IDs to send any signal to a process they would not normally be permitted to signal, including processes owned by other users or by root. The same check enforces jail boundaries, so a jailed process can signal processes on the host or in other jails. Thread IDs are allocated globally and sequentially, and so can be discovered by brute force with no visibility into the target.
An attacker can stop or terminate arbitrary processes, including critical system daemons, resulting in a Denial of Service (DoS).
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| FreeBSD | FreeBSD | unknown |
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Solution
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Workaround
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Fri, 26 Jun 2026 16:30:00 +0000
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cvssV3_1
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Fri, 26 Jun 2026 15:15:00 +0000
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| Description | When used to deliver a signal to a specific thread, thr_kill2(2) called p_cansignal() to determine whether the operation was permitted but did not check the result before delivering the signal. The signal was sent even when the permission check failed. The system call returned the resulting error to the caller, but by then the signal had already been delivered. The missing check allows an unprivileged local user who knows or can guess a target's process and thread IDs to send any signal to a process they would not normally be permitted to signal, including processes owned by other users or by root. The same check enforces jail boundaries, so a jailed process can signal processes on the host or in other jails. Thread IDs are allocated globally and sequentially, and so can be discovered by brute force with no visibility into the target. An attacker can stop or terminate arbitrary processes, including critical system daemons, resulting in a Denial of Service (DoS). | |
| Title | Missing permission check in thr_kill2(2) | |
| Weaknesses | CWE-269 | |
| References |
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Projects
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MITRE
Status: PUBLISHED
Assigner: freebsd
Published:
Updated: 2026-06-26T15:30:02.071Z
Reserved: 2026-05-11T16:27:44.891Z
Link: CVE-2026-45256
Vulnrichment
Updated: 2026-06-26T15:29:56.651Z
NVD
No data.
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-06-26T17:30:05Z