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CVE-2026-44638

CVE-2026-44638 · libsixel: NULL pointer dereference

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

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.

CVSS 2.5 · Low · EPSS 0.1% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • libsixel

    Versions
    • >= 1.0.0, < 1.8.7-r2: Affected

    No fix published

  • libsixel Debian:12

    Versions
    • 1.10.3-3
    • 1.10.5-1
    • 1:1.8.7-1
    • 1:1.8.7-2
    • 1:1.8.7-3
    • 1:1.8.7-4
    • 1:1.8.7-5
    • 1:1.8.7-6
    • 1:1.8.7-r2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libsixel Debian:13

    Versions
    • 1.10.5-1
    • 1:1.8.7-1
    • 1:1.8.7-2
    • 1:1.8.7-3
    • 1:1.8.7-4
    • 1:1.8.7-5
    • 1:1.8.7-6
    • 1:1.8.7-r2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libsixel Debian:14

    Versions
    • 1.10.5-1
    • 1:1.8.7-1
    • 1:1.8.7-2
    • 1:1.8.7-3
    • 1:1.8.7-4
    • 1:1.8.7-5
    • 1:1.8.7-6
    Affected ranges
    • ECOSYSTEM: < 1:1.8.7-r2-1

    Update to 1:1.8.7-r2-1

  • libsixel Ubuntu:16.04:LTS

    Versions
    • 1.4.2-1
    • 1.5.2-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libsixel Ubuntu:18.04:LTS

    Versions
    • 1.5.2-2
    • 1.7.3-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libsixel Ubuntu:20.04:LTS

    Versions
    • 1.8.2-1
    • 1.8.2-2.1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libsixel Ubuntu:22.04:LTS

    Versions
    • 1.8.6-2
    • 1.10.3-2
    • 1.10.3-3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libsixel Ubuntu:24.04:LTS

    Versions
    • 1.10.3-3
    • 1.10.3-3build1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libsixel Ubuntu:25.10

    Versions
    • 1.10.5-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libsixel Ubuntu:26.10

    Versions
    • 1.10.5-1build1
    • 1:1.8.7-r2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libsixel Ubuntu:26.04:LTS

    Versions
    • 1.10.5-1
    • 1.10.5-1build1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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