p PatchFirst

CVE-2026-32853

CVE-2026-32853 · LibVNCServer UltraZip Encoding Heap Out-of-bounds Read

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

This page shows selected source facts. See the linked advisories for the complete description and affected versions.

LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read vulnerability in the UltraZip encoding handler that allows a malicious VNC server to cause information disclosure or application crash. Attackers can exploit improper bounds checking in the HandleUltraZipBPP() function by manipulating subrectangle header counts to read beyond the allocated heap buffer.

CVSS 6.9 · Medium · EPSS 0.4% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • libvncserver

    Versions
    • ≥ 0, ≤ 0.9.15: Affected (semver)
    • 009008e2f4d5a54dd71f422070df3af7b3dbc931: Not affected (git)

    No fix published

  • libvncserver Debian:12

    Versions
    • 0.9.14+dfsg-1
    Affected ranges
    • ECOSYSTEM: < 0.9.14+dfsg-1+deb12u1

    Update to 0.9.14+dfsg-1+deb12u1

  • libvncserver Debian:13

    Versions
    • 0.9.15+dfsg-1
    Affected ranges
    • ECOSYSTEM: < 0.9.15+dfsg-1+deb13u1

    Update to 0.9.15+dfsg-1+deb13u1

  • libvncserver Debian:14

    Versions
    • 0.9.15+dfsg-1
    • 0.9.15+dfsg-2
    Affected ranges
    • ECOSYSTEM: < 0.9.15+dfsg-3

    Update to 0.9.15+dfsg-3

  • tightvnc Ubuntu:Pro:14.04:LTS

    Versions
    • 1.3.9-6.4
    • 1.3.9-6.4ubuntu1
    • 1.3.9-6.5+deb8u1build0.14.04.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • x11vnc Ubuntu:14.04:LTS

    Versions
    • 0.9.13-1.1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libvncserver Ubuntu:16.04:LTS

    Versions
    • 0.9.10+dfsg-3
    • 0.9.10+dfsg-3build1
    • 0.9.10+dfsg-3ubuntu0.16.04.1
    • 0.9.10+dfsg-3ubuntu0.16.04.2
    • 0.9.10+dfsg-3ubuntu0.16.04.3
    • 0.9.10+dfsg-3ubuntu0.16.04.4
    • 0.9.10+dfsg-3ubuntu0.16.04.5
    • 0.9.10+dfsg-3ubuntu0.16.04.6
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • vino Ubuntu:16.04:LTS

    Versions
    • 3.8.1-0ubuntu6
    • 3.8.1-0ubuntu7
    • 3.8.1-0ubuntu8
    • 3.8.1-0ubuntu9
    • 3.8.1-0ubuntu9.1
    • 3.8.1-0ubuntu9.2
    • 3.8.1-0ubuntu9.3
    • 3.8.1-0ubuntu9.4
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • italc Ubuntu:16.04:LTS

    Versions
    • 1:2.0.2+dfsg1-3
    • 1:2.0.2+dfsg1-4
    • 1:2.0.2+dfsg1-4ubuntu0.1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • tightvnc Ubuntu:16.04:LTS

    Versions
    • 1.3.10-0ubuntu2
    • 1.3.10-0ubuntu3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • x11vnc Ubuntu:Pro:16.04:LTS

    Versions
    • 0.9.13-1.2build1
    • 0.9.13-1.2ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libvncserver Ubuntu:18.04:LTS

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

    No fix published

  • vino Ubuntu:18.04:LTS

    Versions
    • 3.8.1-0ubuntu12
    • 3.22.0-2ubuntu1
    • 3.22.0-3ubuntu1
    • 3.22.0-3ubuntu1.1
    • 3.22.0-3ubuntu1.2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • italc Ubuntu:18.04:LTS

    Versions
    • 1:3.0.3+dfsg1-1
    • 1:3.0.3+dfsg1-2
    • 1:3.0.3+dfsg1-2build1
    • 1:3.0.3+dfsg1-2ubuntu1
    • 1:3.0.3+dfsg1-3
    • 1:3.0.3+dfsg1-3ubuntu0.1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • tightvnc Ubuntu:18.04:LTS

    Versions
    • 1.3.10-0ubuntu3
    • 1.3.10-0ubuntu4
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • x11vnc Ubuntu:Pro:18.04:LTS

    Versions
    • 0.9.13-2
    • 0.9.13-2build1
    • 0.9.13-3
    • 0.9.13-3ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libvncserver Ubuntu:20.04:LTS

    Versions
    • 0.9.11+dfsg-1.3
    • 0.9.12+dfsg-3ubuntu3
    • 0.9.12+dfsg-6
    • 0.9.12+dfsg-7
    • 0.9.12+dfsg-8
    • 0.9.12+dfsg-9
    • 0.9.12+dfsg-9ubuntu0.1
    • 0.9.12+dfsg-9ubuntu0.2
    • 0.9.12+dfsg-9ubuntu0.3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • vino Ubuntu:20.04:LTS

    Versions
    • 3.22.0-5ubuntu2
    • 3.22.0-5ubuntu2.1
    • 3.22.0-5ubuntu2.2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • tightvnc Ubuntu:20.04:LTS

    Versions
    • 1.3.10-0ubuntu5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • veyon Ubuntu:20.04:LTS

    Versions
    • 4.2.4+repack1-2
    • 4.2.5+repack1-1
    • 4.3.1+repack1-1
    • 4.3.1+repack1-2
    • 4.3.1+repack1-2build1
    • 4.3.1+repack1-2build2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • x11vnc Ubuntu:Pro:20.04:LTS

    Versions
    • 0.9.13-6
    • 0.9.16-3
    • 0.9.16-3ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libvncserver Ubuntu:22.04:LTS

    Versions
    • 0.9.13+dfsg-3
    • 0.9.13+dfsg-3build1
    • 0.9.13+dfsg-3build2
    Affected ranges
    • ECOSYSTEM: < 0.9.13+dfsg-3ubuntu0.1

    Update to 0.9.13+dfsg-3ubuntu0.1

  • tightvnc Ubuntu:22.04:LTS

    Versions
    • 1:1.3.10-3
    • 1:1.3.10-5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • veyon Ubuntu:22.04:LTS

    Versions
    • 4.5.3+repack1-1build1
    • 4.5.3+repack1-1build2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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