CVE-2026-34001: Xorg: xwayland: x.org x server: use-after-free vulnerability leads to server crash and potential memory corruption

highCVSS 7.8CVE-2026-34001

CSIRTS triage

vendor: X.Org product: Xwayland Memory corruption Remote code execution

What: Use-after-free vulnerability in Xwayland X server leads to memory corruption and server crash.
Who is affected: Desktop systems running Xwayland for X11 protocol forwarding under Wayland.
Urgency: High priority; memory corruption can lead to privilege escalation or remote code execution if exploited.
Action: Update Xwayland to patched version from X.Org.

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

⚡ Watch Xwayland

Get an email when a new Xwayland advisory drops — max one per day, one-click unsubscribe.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.8
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34001

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-2026-340010.26% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 18% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-34001	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

medium[UPDATE] [medium] X.Org X11, Xwayland: Multiple vulnerabilitiescert-bund
high[NEW] [high] Oracle Solaris third-party components: Multiple vulnerabilitiescert-bund

Recent advisories for Xorg

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-34003: Xorg: xwayland: x.org x server: information exposure and denial of service via out-of-bounds m…msrc · 2026-08-06
highCVE-2026-55999: xorg-server / xwayland glamor font atlas Heap Buffer Overflowmsrc · 2026-07-14
unknownCVE-2026-56000: xorg-x11-server / xwayland GLX contextTags Use-After-Free in CommonMakeCurrent()msrc · 2026-07-14
highCVE-2026-56000: Local attackers with a X connection able to provide GLX commit to the X server xorg-server bef…nvd · 2026-07-08
highCVE-2026-55999: Local attackers with a X connection able to provide PCX fonts to the X server xorg-server befo…nvd · 2026-07-08
mediumCVE-2026-50263: Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free information disclos…msrc · 2026-06-09