# CVE-2026-32853: libvncserver: LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read vulnerability in t...

CVE-2026-32853 is fixed in 4 products on 1 platform, first by DEBIAN-CVE-2026-32853, released March 24, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-32853
- Priority: High
- CVSS: 8.1 (high)
- EPSS: 0.0045
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 24, 2026

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | LibVNCServer opensuse-leap 15.6 | 0.9.14-150600.3.6.1 | [SUSE-SU-2026:1173-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-1173-1.md) | Apr 2, 2026 |
| Linux | LibVNCServer opensuse-leap 16.0 | 0.9.14-160000.4.1 | [OPENSUSE-SU-2026:20552-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20552-1.md) | Apr 16, 2026 |
| Linux | LibVNCServer sles 15.7 | 0.9.14-150600.3.6.1 | [SUSE-SU-2026:1173-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-1173-1.md) | Apr 2, 2026 |
| Linux | LibVNCServer sles 16.0 | 0.9.14-160000.4.1 | [SUSE-SU-2026:21206-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-21206-1.md) | Apr 16, 2026 |
| Linux | libvncclient1 Ubuntu 22.04.1 LTS (jammy) | 0.9.13+dfsg-3ubuntu0.1 | [libvncclient1 0.9.13+dfsg-3ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libvncclient1-0.9.13-dfsg-3ubuntu0.1.md) | Jun 24, 2026 |
| Linux | libvncclient1 Ubuntu 24.04.5 LTS (noble) | 0.9.14+dfsg-1ubuntu0.1 | [libvncclient1 0.9.14+dfsg-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libvncclient1-0.9.14-dfsg-1ubuntu0.1.md) | Jun 24, 2026 |
| Linux | libvncclient1 Ubuntu 25.10 (questing) | 0.9.15+dfsg-1ubuntu0.1 | [libvncclient1 0.9.15+dfsg-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libvncclient1-0.9.15-dfsg-1ubuntu0.1.md) | Jun 24, 2026 |
| Linux | libvncserver Debian 12.15 (bookworm) | 0.9.14+dfsg-1+deb12u1 | [DEBIAN-CVE-2026-32853](https://patchblox.com/security/data/fix/linux/debian-cve-2026-32853.md) | Mar 24, 2026 |
| Linux | libvncserver Debian 13.5 (trixie) | 0.9.15+dfsg-1+deb13u1 | [DEBIAN-CVE-2026-32853](https://patchblox.com/security/data/fix/linux/debian-cve-2026-32853.md) | Mar 24, 2026 |
| Linux | libvncserver Debian 14 | 0.9.15+dfsg-3 | [DEBIAN-CVE-2026-32853](https://patchblox.com/security/data/fix/linux/debian-cve-2026-32853.md) | Mar 24, 2026 |
| Linux | libvncserver1 Ubuntu 22.04.1 LTS (jammy) | 0.9.13+dfsg-3ubuntu0.1 | [libvncserver1 0.9.13+dfsg-3ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libvncserver1-0.9.13-dfsg-3ubuntu0.1.md) | Jun 24, 2026 |
| Linux | libvncserver1 Ubuntu 24.04.5 LTS (noble) | 0.9.14+dfsg-1ubuntu0.1 | [libvncserver1 0.9.14+dfsg-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libvncserver1-0.9.14-dfsg-1ubuntu0.1.md) | Jun 24, 2026 |
| Linux | libvncserver1 Ubuntu 25.10 (questing) | 0.9.15+dfsg-1ubuntu0.1 | [libvncserver1 0.9.15+dfsg-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libvncserver1-0.9.15-dfsg-1ubuntu0.1.md) | Jun 24, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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