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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| LibVNC | LibVNCServer | ≤ 0.9.15 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libvncserver | 0.9.15+dfsg-3 | — |
| Debian 13 | libvncserver | 0.9.15+dfsg-1+deb13u1 | — |
| Debian 12 | libvncserver | 0.9.14+dfsg-1+deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | veyon +2 | No fix yet | — |
| Ubuntu 26.04 LTS | libvncserver | 0.9.15+dfsg-3ubuntu0.1 | USN-8463-1 |
| Ubuntu 26.04 LTS | veyon +2 | No fix yet | — |
| Ubuntu 25.10 | libvncserver | 0.9.15+dfsg-1ubuntu0.1 | USN-8463-1 |
| Ubuntu 25.10 | vino +3 | No fix yet | — |
| Ubuntu 24.04 LTS | libvncserver | 0.9.14+dfsg-1ubuntu0.1 | USN-8463-1 |
| Ubuntu 24.04 LTS | vino +3 | No fix yet | — |
| Ubuntu 22.04 LTS | libvncserver | 0.9.13+dfsg-3ubuntu0.1 | USN-8463-1 |
| Ubuntu 22.04 LTS | vino +3 | No fix yet | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | vino +3 | No fix yet | — |
| Ubuntu 18.04 LTS | vino +3 | No fix yet | — |
| Ubuntu 16.04 LTS | vino +3 | No fix yet | — |
| Ubuntu 14.04 LTS | x11vnc | No fix yet | — |
| Ubuntu Pro 20.04 LTS | x11vnc | No fix yet | — |
| Ubuntu Pro 18.04 LTS | x11vnc | No fix yet | — |
| Ubuntu Pro 16.04 LTS | x11vnc | No fix yet | — |
| Ubuntu Pro 14.04 LTS | tightvnc | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | LibVNCServer | 0.9.10-150000.4.35.1 | SUSE-SU-2026:1173-1, SUSE-SU-2026:1124-1 |
| SLES 12 SP5 | LibVNCServer | 0.9.9-17.44.1 | SUSE-SU-2026:1174-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | LibVNCServer | 0.9.14-160000.4.1 | SUSE-SU-2026:21206-1 |
| SLES 16.0 | LibVNCServer | 0.9.14-160000.4.1 | SUSE-SU-2026:21206-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | LibVNCServer | 0.9.15-2.1 | openSUSE-SU-2026:10433-1 |
| openSUSE Leap 16.0 | LibVNCServer | 0.9.14-160000.4.1 | openSUSE-SU-2026:20552-1 |
| openSUSE Leap 15.6 | LibVNCServer | 0.9.14-150600.3.6.1 | SUSE-SU-2026:1173-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | libvncserver +1 | 0.9.9-14.amzn2.0.2 | ALAS2-2026-3247 |
Advisories 8
- USN-8463-1 libvncserver vulnerabilities Ubuntu Security Notices (USN) · Jun 23, 2026
- openSUSE-SU-2026:20552-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Apr 22, 2026
- SUSE-SU-2026:21206-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Apr 22, 2026
- ALAS2-2026-3247 Moderate: libvncserver security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Apr 13, 2026
- SUSE-SU-2026:1174-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Apr 3, 2026
- SUSE-SU-2026:1173-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Apr 3, 2026
- SUSE-SU-2026:1124-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Mar 29, 2026
- openSUSE-SU-2026:10433-1 LibVNCServer-devel-0.9.15-2.1 on GA media SUSE / openSUSE Security Updates · Mar 27, 2026