X.Org X server: Heap buffer overflow in XFixes pointer barriers
Summary
A buffer overflow in the handling of pointer barriers in the XFIXES extension affects the X.Org X server before 21.1.25 and XWayland before 24.1.14. An authenticated X client can exploit it to crash the X server or potentially execute code in the server context. Exploitation requires local access and code running in an active X11 session.
Affected
- X.Org X server before 21.1.25
- XWayland before 24.1.14
Fixed in
- X.Org X server 21.1.25
- XWayland 24.1.14
- Check your distribution's advisory for the exact package build, as backports may use different version strings.
Workaround
Unknown. No vendor workaround is documented.
- Reduce the number of untrusted programs that can connect to your X session until patching is complete.
Exploitation
- No public proof of concept found.
- Not listed in CISA KEV.
- No known in-the-wild exploitation.
- EPSS 0.2 % (not independently verified).
Our recommendation
- Update the X.Org X server and XWayland packages with the next regular update cycle, and sooner on multi-user hosts, terminal servers and shared workstations.
- Check your fleet for X.Org X server and XWayland with 'Xorg -version' or 'xwayland --version'.
- Do not allow X over the network (for example TCP listening or XDMCP) on servers.
- Headless servers without a running X server have low exposure.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Fix commit gitlab.freedesktop.org
- X.Org security advisories www.x.org
- CVE description and CWE cve.threatint.com
- Help Net Security coverage www.helpnetsecurity.com
- 9to5Linux release coverage 9to5linux.com
- SUSE advisory coverage linuxsecurity.com
- Nixpkgs tracker github.com
- OpenCVE CVE-2026-93519 app.opencve.io
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 21:53.
Original description (NVD)
A buffer overflow when handling pointer barriers in the XFIXES extension in X.Org X server before 21.1.25 and XWayland before 24.1.14 could be used by authenticated X clients to crash or potentially execute code in X server context.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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