CVE-2026-56000: xorg-x11-server / xwayland GLX contextTags Use-After-Free in CommonMakeCurrent()

CSIRTS triage

What

There is a use-after-free in GLX contextTags in CommonMakeCurrent().

Who is affected

Deployments of xorg-x11-server are affected.

Urgency

Remediation urgency is unknown due to lack of severity information.

Action

Monitor for updates regarding this vulnerability.

AI-assisted analysis generated from the source advisory — verify against the original.

Details

Source

Microsoft Security Response Center (INTL · vendor-psirt · site)

Severity

unknown

Published

2026-07-14

Exploitation

Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56000

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

• Low exploitation riskCVE-2026-560000.22% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 13% of all EPSS-scored CVEs.

Referenced CVEs

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

• high[NEW] [high] X.Org X11 and Xwayland: Multiple vulnerabilities allow code execution and DoScert-bund
• unknownMultiple vulnerabilities in Microsoft Azure Linux (July 15, 2026)cert-fr-avis
• highCVE-2026-56000: Local attackers with a X connection able to provide GLX commit to the X server xorg-server bef…nvd

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