p PatchFirst

CVE-2026-33636

CVE-2026-33636 · LIBPNG has ARM NEON Palette Expansion Out-of-Bounds Read on AArch64

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

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. In versions 1.6.36 through 1.6.55, an out-of-bounds read and write exists in libpng's ARM/AArch64 Neon-optimized palette expansion path. When expanding 8-bit paletted rows to RGB or RGBA, the Neon loop processes a final partial chunk without verifying that enough input pixels remain. Because the implementation works backward from the end of the row, the final iteration dereferences pointers before the start of the row buffer (OOB read) and writes expanded pixel data to the same underflowed positions (OOB write). This is reachable via normal decoding of attacker-controlled PNG input if Neon is enabled. Version 1.6.56 fixes the issue.

CVSS 7.6 · High · EPSS 0.8% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • libpng

    Versions
    • >= 1.6.36, < 1.6.56: Affected

    No fix published

  • libpng1.6 Debian:12

    Versions
    • 1.6.39-2
    • 1.6.39-2+deb12u1
    • 1.6.39-2+deb12u2
    • 1.6.39-2+deb12u3
    Affected ranges
    • ECOSYSTEM: < 1.6.39-2+deb12u4

    Update to 1.6.39-2+deb12u4

  • libpng1.6 Debian:13

    Versions
    • 1.6.48-1
    • 1.6.48-1+deb13u1
    • 1.6.48-1+deb13u2
    • 1.6.48-1+deb13u3
    Affected ranges
    • ECOSYSTEM: < 1.6.48-1+deb13u4

    Update to 1.6.48-1+deb13u4

  • libpng1.6 Debian:14

    Versions
    • 1.6.48-1
    • 1.6.49-1~exp1
    • 1.6.50-1
    • 1.6.50-1~exp1
    • 1.6.51-1
    • 1.6.52-1
    • 1.6.53-1
    • 1.6.54-1
    • 1.6.55-1
    Affected ranges
    • ECOSYSTEM: < 1.6.56-1

    Update to 1.6.56-1

  • libpng1.6 Ubuntu:Pro:20.04:LTS

    Versions
    • 1.6.37-1
    • 1.6.37-2
    • 1.6.37-2ubuntu0.1~esm1
    • 1.6.37-2ubuntu0.1~esm2
    Affected ranges
    • ECOSYSTEM: < 1.6.37-2ubuntu0.1~esm3

    Update to 1.6.37-2ubuntu0.1~esm3

  • libpng1.6 Ubuntu:22.04:LTS

    Versions
    • 1.6.37-3build4
    • 1.6.37-3build5
    • 1.6.37-3ubuntu0.1
    • 1.6.37-3ubuntu0.3
    • 1.6.37-3ubuntu0.4
    Affected ranges
    • ECOSYSTEM: < 1.6.37-3ubuntu0.5

    Update to 1.6.37-3ubuntu0.5

  • libpng1.6 Ubuntu:24.04:LTS

    Versions
    • 1.6.40-1
    • 1.6.40-2
    • 1.6.40-3
    • 1.6.42-1
    • 1.6.43-1
    • 1.6.43-3
    • 1.6.43-5build1
    • 1.6.43-5ubuntu0.1
    • 1.6.43-5ubuntu0.3
    • 1.6.43-5ubuntu0.4
    • 1.6.43-5ubuntu0.5
    Affected ranges
    • ECOSYSTEM: < 1.6.43-5ubuntu0.6

    Update to 1.6.43-5ubuntu0.6

  • libpng1.6 Ubuntu:25.10

    Versions
    • 1.6.47-1.1
    • 1.6.48-1
    • 1.6.49-1~exp1
    • 1.6.50-1~exp1
    • 1.6.50-1
    • 1.6.50-1ubuntu0.1
    • 1.6.50-1ubuntu0.3
    • 1.6.50-1ubuntu0.4
    Affected ranges
    • ECOSYSTEM: < 1.6.50-1ubuntu0.5

    Update to 1.6.50-1ubuntu0.5

Original sources

Check your server →