X11vnc Vulnerability — Ubuntu Security Update (USN-9089-1)
USN-9089-1 updates Ubuntu 20.04, Ubuntu 22.04: It was discovered that x11vnc created shared memory segments with insecure permissions. Apply the update via standard apt tooling.
What this means under a SharedLicense license
The advisory's own severity data peaks at CVSS ; unpatched Ubuntu 20.04, Ubuntu 22.04 servers remain exposed until updated.
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USN-9089-1
Publication date
12 November 2026
Overview
x11vnc could be made to expose sensitive information to local users.
Releases
Packages
- x11vnc – VNC server to allow remote access to an existing X session
Details
It was discovered that x11vnc created shared memory segments with insecure
permissions. A local attacker could possibly use this issue to obtain
sensitive information or modify screen contents.
It was discovered that x11vnc created shared memory segments with insecure
permissions. A local attacker could possibly use this issue to obtain
sensitive information or modify screen contents.
Update instructions
After a standard system update you need to restart x11vnc to make all the
necessary changes.
Learn more about how to get the fixes.
The problem can be corrected by updating your system to the following package versions:
| Ubuntu Release | Package Version | ||
|---|---|---|---|
| 20.04 LTS focal | x11vnc – 0.9.16-3ubuntu0.1~esm2 Ubuntu Pro Fix available with Ubuntu Pro via ESM Apps. A community fix might become publicly available in the future. | ||
References
Frequently Asked Questions
What does USN-9089-1 fix?
Which Ubuntu releases are covered?
How do I apply it?
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