CVE-2026-42304

Twisted: Denial of Service (DoS) in twisted.names via Crafted DNS Compression Pointer Chains

Published May 13, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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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
Ubuntu USN Ubuntu USN USN-8380-1 Twisted vulnerability
History
Type Values Removed Values Added
CPEs cpe:2.3:a:twisted:twisted:*:*:*:*:*:*:*:*
cpe:2.3:a:twisted:twisted:26.4.0:rc1:*:*:*:*:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

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

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 14, 2026, 3:45 PM
Reserved
Apr 26, 2026, 12:13 PM
Status
Analyzed
Published
May 13, 2026, 9:16 PM
Modified
Nov 11, 2026, 8:10 PM