CVE-2026-93542 Out-of-bounds read in libXi's XI2 class parsing via size_classes() and copy_classes()
A malicious server can crash an X client via an out-of-bounds read in libXi's XI2 class parsing functions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-93542?
CVE-2026-93542 is a medium-severity memory corruption vulnerability in x.org libXi, published on 24 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
An out-of-bounds read in libXi's XI2 class parsing via size_classes() and copy_classes() in libXi before 1.8.4 could be used by malicous servers to crash the X client.
Weakness: CWE-125
Which versions are affected by CVE-2026-93542?
How do I fix CVE-2026-93542?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-93542 being exploited?
There is no known exploitation of CVE-2026-93542 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-93542, AZL-104063, BELL-CVE-2026-93542, DEBIAN-CVE-2026-93542, ECHO-d0d5-c264-89ec, GHSA-p88p-rg7m-cc93 and 1 more.