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CVE-2026-23879

CVE-2026-23879 · py7zr: Arbitrary File Write Vulnerability

This page contains facts from public vulnerability sources. Check the original advisory before updating.

py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Versions 1.1.2 and below contain an an arbitrary file write vulnerability, which allows symbolic links to be recreated outside the destination directory via crafted malicious symbolic link chains. When using extractall to extract an archive, the library restores these symbolic links, linking them to arbitrary directories on the host file system. During extraction, the program only checks the link arcname within the destination directory, but ignores the combined symlink path resolution. Attackers can exploit this vulnerability by constructing malicious archives, thereby bypassing the directory boundary restrictions implemented by the extractor. Subsequent extraction of regular files through these symbolic links can result in arbitrary file writes. This vulnerability may lead to remote code execution, privilege escalation, data corruption, or denial of service. This issue has been fixed in version 1.1.3.

CVSS 8.0 · High · EPSS 0.5% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • py7zr

    Versions
    • < 1.1.3: Affected

    No fix published

  • py7zr Debian:12

    Versions
    • 0.11.3+dfsg-5
    • 0.11.3+dfsg-6
    • 0.11.3+dfsg-7
    • 0.11.3+dfsg-8
    • 0.21.0+dfsg-1
    • 0.21.0+dfsg-2
    • 0.21.1+dfsg-1
    • 0.22.0+dfsg-1
    • 1.0.0+dfsg1-1
    • 1.0.0+dfsg1-2
    • 1.0.0+dfsg1-3
    • 1.0.0+dfsg1-3~bpo13+1
    • 1.0.0+dfsg1-4
    • 1.0.0+dfsg1-5
    • 1.1.0+dfsg-1~exp1
    • 1.1.2+dfsg-1
    • 1.1.2+dfsg-1~exp1
    • 1.1.2+dfsg-2
    • 1.1.2+really1.1.0+dfsg-1
    • 1.1.2-1+really1.1.0+dfsg-1
    • 1.1.2-1+really1.1.0+dfsg-2
    • 1.1.3+dfsg-1
    • 1.1.3+dfsg-2
    • 1.1.3+dfsg-3
    • 1.1.3+dfsg-4
    • 1.1.4+dfsg-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • py7zr Debian:13

    Versions
    • 0.22.0+dfsg-1
    • 1.0.0+dfsg1-1
    • 1.0.0+dfsg1-2
    • 1.0.0+dfsg1-3
    • 1.0.0+dfsg1-3~bpo13+1
    • 1.0.0+dfsg1-4
    • 1.0.0+dfsg1-5
    • 1.1.0+dfsg-1~exp1
    • 1.1.2+dfsg-1
    • 1.1.2+dfsg-1~exp1
    • 1.1.2+dfsg-2
    • 1.1.2+really1.1.0+dfsg-1
    • 1.1.2-1+really1.1.0+dfsg-1
    • 1.1.2-1+really1.1.0+dfsg-2
    • 1.1.3+dfsg-1
    • 1.1.3+dfsg-2
    • 1.1.3+dfsg-3
    • 1.1.3+dfsg-4
    • 1.1.4+dfsg-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • py7zr Debian:14

    Versions
    • 0.22.0+dfsg-1
    • 1.0.0+dfsg1-1
    • 1.0.0+dfsg1-2
    • 1.0.0+dfsg1-3
    • 1.0.0+dfsg1-3~bpo13+1
    • 1.0.0+dfsg1-4
    • 1.0.0+dfsg1-5
    • 1.1.0+dfsg-1~exp1
    • 1.1.2+dfsg-1~exp1
    Affected ranges
    • ECOSYSTEM: < 1.1.2+dfsg-1

    Update to 1.1.2+dfsg-1

  • py7zr PyPI

    Versions
    • 0.0.3
    • 0.0.4
    • 0.0.5
    • 0.0.6
    • 0.0.7
    • 0.0.8
    • 0.1.0
    • 0.1.1
    • 0.1.2
    • 0.1.3
    • 0.1.4
    • 0.1.5
    • 0.1.6
    • 0.10.0
    • 0.10.0a1
    • 0.10.0a2
    • 0.10.0a3
    • 0.10.0a4
    • 0.10.0a5
    • 0.10.0a6
    • 0.10.0b1
    • 0.10.0b3
    • 0.10.1
    • 0.10.2
    • 0.11.0
    • 0.11.0a1
    • 0.11.0b1
    • 0.11.0b2
    • 0.11.0b3
    • 0.11.1
    • 0.11.2
    • 0.11.3
    • 0.12.0
    • 0.13.0
    • 0.13.1
    • 0.14.0
    • 0.14.1
    • 0.15.0
    • 0.15.1
    • 0.15.2
    • 0.16.0
    • 0.16.1
    • 0.16.2
    • 0.16.3
    • 0.16.4
    • 0.17.0
    • 0.17.1
    • 0.17.2
    • 0.17.3
    • 0.17.4
    • 0.18.0
    • 0.18.1
    • 0.18.10
    • 0.18.11
    • 0.18.12
    • 0.18.3
    • 0.18.4
    • 0.18.5
    • 0.18.6
    • 0.18.7
    • 0.18.9
    • 0.19.0
    • 0.19.1
    • 0.19.2
    • 0.2.0
    • 0.20.0
    • 0.20.1
    • 0.20.2
    • 0.20.4
    • 0.20.5
    • 0.20.6
    • 0.20.7
    • 0.20.8
    • 0.21.0
    • 0.21.1
    • 0.22.0
    • 0.3
    • 0.3.1
    • 0.3.2
    • 0.3.3
    • 0.3.4
    • 0.3.5
    • 0.4
    • 0.4.1
    • 0.4.3
    • 0.4.4
    • 0.4a1
    • 0.4a2
    • 0.4b1
    • 0.5
    • 0.5.2
    • 0.5.3
    • 0.5.4
    • 0.5.5
    • 0.5a3
    • 0.5a4
    • 0.5b1
    • 0.5b2
    • 0.5b3
    • 0.5b4
    • 0.5b5
    • 0.5b6
    • 0.5rc2
    • 0.5rc3
    • 0.6
    • 0.6a1
    • 0.6a2
    • 0.6b1
    • 0.6b2
    • 0.6b3
    • 0.6b4
    • 0.6b5
    • 0.6b6
    • 0.6b7
    • 0.6b8
    • 0.6rc0
    • 0.7.0
    • 0.7.0b1
    • 0.7.0b2
    • 0.7.0b3
    • 0.7.1
    • 0.7.2
    • 0.7.3
    • 0.7.4
    • 0.8.0
    • 0.8.0a1
    • 0.8.0a2
    • 0.8.0a3
    • 0.8.0b1
    • 0.8.0b2
    • 0.8.0b3
    • 0.8.0b4
    • 0.8.0b5
    • 0.8.0b6
    • 0.8.0b7
    • 0.8.0b8
    • 0.8.1
    • 0.8.2
    • 0.8.3
    • 0.8.4
    • 0.8.5
    • 0.9.0
    • 0.9.0a1
    • 0.9.0a2
    • 0.9.0b1
    • 0.9.0b2
    • 0.9.0b3
    • 0.9.1
    • 0.9.10
    • 0.9.2
    • 0.9.3
    • 0.9.4
    • 0.9.5
    • 0.9.7
    • 0.9.8
    • 0.9.9
    • 1.0.0
    • 1.0.0rc1
    • 1.0.0rc2
    • 1.0.0rc3
    • 1.1.0
    • 1.1.0rc2
    • 1.1.0rc4
    • 1.1.2
    Affected ranges
    • ECOSYSTEM: < 1.1.3

    Update to 1.1.3

  • py7zr Ubuntu:22.04:LTS

    Versions
    • 0.11.3+dfsg-1
    • 0.11.3+dfsg-1ubuntu1
    • 0.11.3+dfsg-2
    • 0.11.3+dfsg-3
    • 0.11.3+dfsg-4
    • 0.11.3+dfsg-4ubuntu0.1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • py7zr Ubuntu:24.04:LTS

    Versions
    • 0.11.3+dfsg-6
    • 0.11.3+dfsg-7
    • 0.11.3+dfsg-8
    • 0.11.3+dfsg-8build1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • py7zr Ubuntu:25.10

    Versions
    • 0.22.0+dfsg-1
    • 1.0.0+dfsg1-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • py7zr Ubuntu:26.10

    Versions
    • 1.1.2+dfsg-1
    • 1.1.2-1+really1.1.0+dfsg-2
    • 1.1.3+dfsg-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • py7zr Ubuntu:26.04:LTS

    Versions
    • 1.0.0+dfsg1-1
    • 1.0.0+dfsg1-3
    • 1.0.0+dfsg1-4
    • 1.0.0+dfsg1-5
    • 1.1.2+dfsg-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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