PYSEC-2026-160

    Dashboard / Vulnerabilities / PYSEC-2026-160

    PYSEC-2026-160

    Published: 13 May 2026Last Modified: 20 May 2026

    Summary:

    Details: 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.

    References: https://github.com/twisted/twisted/security/advisories/GHSA-grgv-6hw6-v9g4

    Affected packages

    Package

    Name: twisted

    Purl: pkg:pypi/twisted

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -26.4.0

    Affected versions

    1.0.1
    1.0.3
    1.0.4
    1.0.5
    1.0.6
    1.0.7

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High