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CVE-2026-32853VulnerabilityPublished Updated

Tightvnc: LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read

Affects tightvncSource GCVE Database

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Authoritative record:CVE-2026-32853· Medium 6.9

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

CVSS 4.0 base score
6.9Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (VulnCheck)CVSS 4.06.9
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 24 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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).

Affected software

ProductAffectedFixed in
Ubuntu 26.10tightvncpkg:deb/ubuntu/tightvnc?arch=source&distro=stonkingOther threatsAffected
  • =1:1.3.10-10build1
  • =1:1.3.10-11
Fixed in–
Ubuntu 26.10veyonpkg:deb/ubuntu/veyon?arch=source&distro=stonkingOther threatsAffected
  • 4.9.7+repack1-1.1 – 4.9.7+repack1-1build1
4 affected builds
Fixed in–
Ubuntu 26.10x11vncpkg:deb/ubuntu/x11vnc?arch=source&distro=stonkingOther threatsAffected
  • =0.9.17-2
  • =0.9.17-3
  • =0.9.17-3build1
Fixed in–
Ubuntu 26.04 LTStightvncpkg:deb/ubuntu/tightvnc?arch=source&distro=resoluteOther threatsAffected
  • =1:1.3.10-10
  • =1:1.3.10-10build1
Fixed in–
Ubuntu 26.04 LTSveyonpkg:deb/ubuntu/veyon?arch=source&distro=resoluteOther threatsAffected
  • =4.9.7+repack1-1
  • =4.9.7+repack1-1build1
Fixed in–
Ubuntu 26.04 LTSx11vncpkg:deb/ubuntu/x11vnc?arch=source&distro=resoluteOther threatsAffected
  • =0.9.17-1
  • =0.9.17-2
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

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