Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.4.0rc2, the twisted.names module is vulnerable to a Denial of Service (DoS) attack via resource exhaustion during DNS name decompression. A remote, unauthenticated attacker can exploit this by sending a crafted TCP DNS packet containing deeply chained compression pointers. This flaw bypasses previous loop-prevention logic, causing the single-threaded Twisted reactor to hang while processing millions of recursive lookups, effectively freezing the server. This vulnerability is fixed in 26.4.0rc2.

Project Subscriptions

Vendors Products
Twisted Subscribe
Twisted Subscribe
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-grgv-6hw6-v9g4 Twisted has a Denial of Service (DoS) in twisted.names via Crafted DNS Compression Pointer Chains
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 13 May 2026 22:45:00 +0000

Type Values Removed Values Added
First Time appeared Twisted
Twisted twisted
Vendors & Products Twisted
Twisted twisted

Wed, 13 May 2026 20:30:00 +0000

Type Values Removed Values Added
Description Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.4.0rc2, the twisted.names module is vulnerable to a Denial of Service (DoS) attack via resource exhaustion during DNS name decompression. A remote, unauthenticated attacker can exploit this by sending a crafted TCP DNS packet containing deeply chained compression pointers. This flaw bypasses previous loop-prevention logic, causing the single-threaded Twisted reactor to hang while processing millions of recursive lookups, effectively freezing the server. This vulnerability is fixed in 26.4.0rc2.
Title Twisted: Denial of Service (DoS) in twisted.names via Crafted DNS Compression Pointer Chains
Weaknesses CWE-400
CWE-407
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-13T20:20:29.149Z

Reserved: 2026-04-26T12:13:55.552Z

Link: CVE-2026-42304

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-13T21:16:46.933

Modified: 2026-05-13T21:16:46.933

Link: CVE-2026-42304

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-13T22:30:05Z

Weaknesses