Bug 2497655

Summary: CVE-2026-42304 python-twisted: Twisted: Denial of Service via crafted DNS packets in twisted.names [fedora-all]
Product: [Fedora] Fedora Reporter: Michalis Papadopoullos <mpapadop>
Component: python-twistedAssignee: Jonathan Wright <jonathan>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: unspecified    
Version: 45CC: eclipseo, jonathan, python-packagers-sig, romain.geissler
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["0b4e394b-8eec-48b8-a539-c6b30c765055"]}
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Description Michalis Papadopoullos 2026-07-07 09:33:30 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.
Comment 1 Aoife Moloney 2026-08-17 15:15:20 UTC 
This bug appears to have been reported against 'rawhide' during the Fedora Linux 45 development cycle.
Changing version to 45.