Quick answers
- Is CVE-2026-93518 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-93518 being exploited in the wild.
- How severe is CVE-2026-93518?
- High severity, with a CVSS score of 7.8, published 28 October 2026.
- Which products and versions are affected?
- X.Org X Server before 21.1.25; X.Org XWayland before 24.1.14.
- Is there a fix for CVE-2026-93518?
- Yes: fixed in X server 21.1.25; XWayland 24.1.14. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-93518 attacked?
- It is attacked over the network or with local access.
- Am I affected by CVE-2026-93518?
- Check whether you run X.Org X Server or X.Org XWayland at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: X server 21.1.25; XWayland 24.1.14
Technical details
An integer truncation vulnerability exists in XkbResizeKeyType() where size_syms and num_syms fields are declared as 16-bit unsigned shorts but computed values are truncated when assigned. When XkbResizeKeyType() calculates (nTotal * 15) / 10, the 32-bit result is implicitly truncated to 16 bits, causing undersized memory allocation followed by out-of-bounds writes. Authenticated X clients can exploit this via XKB SetMap requests to achieve heap buffer overflow.
Affected products
- X.org X server before 21.1.25
- X.org XWayland before 24.1.14
Timeline
- 2026-10-28: disclosed
- 2026-08-26: patched: Commit 89101a6c widened fields from unsigned short to unsigned int