CVE-2018-15853 — Endless recursion exists in xkbcomp/expr

Endless recursion exists in xkbcomp/expr.c in xkbcommon and libxkbcommon before 0.8.1, which could be used by local attackers to crash xkbcommon users by supplying a crafted keymap file that triggers boolean negation.

01What is this vulnerability?

Endless recursion exists in xkbcomp/expr.c in xkbcommon and libxkbcommon before 0.8.1, which could be used by local attackers to crash xkbcommon users by supplying a crafted keymap file that triggers boolean negation.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2018-08-25T21:00:00.000Z
• Last modified: 2024-08-05T10:10:04.991Z

09References

• security.gentoo.org — https://security.gentoo.org/glsa/201810-05
• usn.ubuntu.com — https://usn.ubuntu.com/3786-1/
• usn.ubuntu.com — https://usn.ubuntu.com/3786-2/
• lists.freedesktop.org — https://lists.freedesktop.org/archives/wayland-devel/2018-August/039232.html
• github.com — https://github.com/xkbcommon/libxkbcommon/commit/1f9d1248c07cda8aaff762429c0dce1…
• access.redhat.com — https://access.redhat.com/errata/RHSA-2019:2079