PYSEC-2026-4343

    Dashboard / Vulnerabilities / PYSEC-2026-4343

    PYSEC-2026-4343

    Published: 21 Oct 2026Last Modified: 29 Oct 2026

    Summary:

    Details: Pillow is a Python imaging library. Prior to 13.0.0 on Windows, src/PIL/WmfImagePlugin.py passes unchecked 32-bit WMF or EMF dimensions to the native drawwmf handler in src/display.c. The handler sizes a DIB allocation from 16-bit-truncated bcWidth and bcHeight fields but copies pixel data using the original full dimensions. A crafted wide, short metafile can pass the pixel-count decompression-bomb check and make the Windows-only renderer read beyond the heap buffer, potentially disclosing memory or crashing the process. 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-9v9v-9qvf-h2hj, https://github.com/python-pillow/Pillow/pull/10120, https://github.com/python-pillow/Pillow/commit/4cf46bee338304c5c8968fd7f132ba0d40c428b7

    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