Vulnerability · Published May 13, 2026 · Assigned by GitHub_M
CVE-2026-42304Twisted: Denial of Service (DoS) in twisted.names via Crafted DNS Compression Pointer Chains
High 7.5
In plain English
A high-severity uncontrolled resource consumption in twisted from twisted. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | twisted | no fix listed | DEBIAN-CVE-2026-42304 |
| Debian:13 | twisted | no fix listed | DEBIAN-CVE-2026-42304 |
| Debian:14 | twisted | 26.4.0-1 | DEBIAN-CVE-2026-42304 |
| PyPI | twisted | 26.4.0 | PYSEC-2026-160 |
| PyPI | twisted | 26.4.0rc2 | GHSA-grgv-6hw6-v9g4 |
| Ubuntu:22.04:LTS | twisted | 22.1.0-2ubuntu2.7 | USN-8380-1 |
| Ubuntu:22.04:LTS | twisted | 22.1.0-2ubuntu2.7 | UBUNTU-CVE-2026-42304 |
| Ubuntu:24.04:LTS | twisted | 24.3.0-1ubuntu0.2 | USN-8380-1 |
| Ubuntu:24.04:LTS | twisted | 24.3.0-1ubuntu0.2 | UBUNTU-CVE-2026-42304 |
| Ubuntu:25.10 | twisted | 24.11.0-1ubuntu0.1 | USN-8380-1 |
| Ubuntu:25.10 | twisted | 24.11.0-1ubuntu0.1 | UBUNTU-CVE-2026-42304 |
| Ubuntu:26.04:LTS | twisted | 25.5.0-5ubuntu0.1 | UBUNTU-CVE-2026-42304 |
| Ubuntu:26.04:LTS | twisted | 25.5.0-5ubuntu0.1 | USN-8380-1 |
Affected products (as reported)
Weakness: CWE-400, CWE-407 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/twisted/twisted/security/advisories/GHSA-grgv-6hw6-v9g4 x_refsource_CONFIRM