PYSEC-2026-4341

    Dashboard / Vulnerabilities / PYSEC-2026-4341

    PYSEC-2026-4341

    Published: 21 Oct 2026Last Modified: 29 Oct 2026

    Summary:

    Details: Pillow is a Python imaging library. Prior to 13.0.0, the TarIO initializer in src/PIL/TarIO.py accepts a negative octal member size and computes a backward seek that returns to the same 512-byte header. When the requested member name does not match, the parser repeatedly reads that header, consumes a full CPU core, and never returns. TarIO is reached only when an application directly uses PIL.TarIO.TarIO rather than the default Image.open() path. This issue is fixed in version 13.0.0.

    References: https://github.com/python-pillow/Pillow/releases/tag/13.0.0, https://github.com/python-pillow/Pillow/security/advisories/GHSA-3j72-p6qg-6xp7, https://github.com/python-pillow/Pillow/pull/10012, https://github.com/python-pillow/Pillow/commit/19b695fdcc5eddc37374e2b1645fc4185edaf71d

    Affected packages

    Package

    Name: pillow

    Purl: pkg:pypi/pillow

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -13.0.0

    Affected versions

    1.0

    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