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Vulnerability record · CVE-2026-42304 · published 13 May 2026

CVE-2026-42304: Twisted uncontrolled resource consumption vulnerability

Twisted · Twisted

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.

7.5 CVSS 3.1 High EPSS 0.95% · top 40.3% CWE-400 · Uncontrolled resource consumptionCWE-407 · CWE-407
7.5CVSS 3.1 base score
0.95%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/twisted/twisted/security/advisories/GHSA-grgv-6hw6-v9g4 ExploitMitigationVendor Advisory
https://github.com/twisted/twisted/security/advisories/GHSA-grgv-6hw6-v9g4 ExploitMitigationVendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2026-42304), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.