Quick answers
- Is CVE-2026-93523 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-93523 being exploited in the wild.
- How severe is CVE-2026-93523?
- High severity, with a CVSS score of 7.8, published 28 October 2026.
- Which products and versions are affected?
- X.Org X Server before 21.1.15; X.Org XWayland before 24.1.14.
- Is there a fix for CVE-2026-93523?
- Yes: fixed in X Server 21.1.15 and later; XWayland 24.1.14 and later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-93523 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-93523?
- 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 21.1.15 and later; XWayland 24.1.14 and later
Technical details
The XIPassiveUngrabDevice request handler fails to validate out-of-range modifier values before passing them to DeletePassiveGrabFromList(), which uses BITCLEAR(mask, modifier) on an 8-word (256-bit) heap-allocated mask. A modifier value exceeding 255 causes out-of-bounds heap access, permitting a controlled single-bit write at an attacker-chosen offset. An authenticated X client can trigger this via a crafted Xi protocol message.
Affected products
- X.Org X Server before 21.1.15
- X.Org XWayland before 24.1.14
Timeline
- 2026-10-28: disclosed
- 2026-08-26: patched