CVE-2026-34003: Xorg: xwayland: x.org x server: information exposure and denial of service via out-of-bounds memory access

highCVSS 7.1CVE-2026-34003

CSIRTS triage

vendor: X.Org product: Xwayland Information disclosure Denial of service

What: Out-of-bounds memory access in Xwayland server enables information disclosure and denial of service attacks.
Who is affected: Users running Xwayland server on systems with Wayland display server.
Urgency: High urgency; memory safety issue enables both information leakage and crash attacks.
Action: Update X.Org Xwayland to a patched version addressing the out-of-bounds access.

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

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.1
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34003

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-2026-340030.25% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 16% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-34003	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.

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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
highCVE-2026-50256: Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in font alia…msrc · 2026-06-09