Tightvnc: LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read
Affects tightvncSource GCVE Database
Not known to be exploited · CVSS 6.9 Medium · fixed in 0.9.13+dfsg-3ubuntu0.1 : update tightvnc when convenient.
Data as of 13 Nov 2026, 13:11 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 6.9 |
|---|
- Patch
- Available – fixed in 0.9.13+dfsg-3ubuntu0.1, 0.9.14+dfsg-1ubuntu0.1, 0.9.15+dfsg-1ubuntu0.1
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 24 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Upgrade the Ubuntu libvncserver to 0.9.13+dfsg-3ubuntu0.1 (package) or 0.9.14+dfsg-1ubuntu0.1 (package) or 0.9.15+dfsg-1ubuntu0.1 (package).
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10tightvncpkg:deb/ubuntu/tightvnc?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10veyonpkg:deb/ubuntu/veyon?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10x11vncpkg:deb/ubuntu/x11vnc?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTStightvncpkg:deb/ubuntu/tightvnc?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSveyonpkg:deb/ubuntu/veyon?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSx11vncpkg:deb/ubuntu/x11vnc?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available and has been released by Ubuntu in updated LibVNCServer packages for affected Ubuntu versions. Users should apply the official security updates as provided in Ubuntu Security Notice USN-8463-1 to remediate this vulnerability. Standard system updates will apply the necessary patches.
Description
LibVNCServer versions 0.9.15 and earlier contain a heap out-of-bounds read vulnerability in the UltraZip encoding handler. This flaw allows a malicious VNC server to cause information disclosure or application crash by exploiting improper bounds checking in the HandleUltraZipBPP() function. The vulnerability affects multiple Ubuntu releases including 22.04 LTS, 24.04 LTS, and 25.04. Fixed versions are available and patches have been released by Ubuntu.
References
- ubuntu.com/security/CVE-2026-32853 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-32853 (opens in a new tab)
- github.com/LibVNC/libvncserver/security/advisories/GHSA-87q7-v983-qwcj (opens in a new tab)
- vulncheck.com/advisories/libvncserver-ultrazip-encoding-heap-out-of-bounds-read (opens in a new tab)
- ubuntu.com/security/notices/USN-8463-1 (opens in a new tab)