What’s Vulnerable › Vulnerabilities

CVE-2018-15853

• Severity: medium (CVSS 5.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-08-25 · updated 2026-06-17
• Weakness: CWE-400

Description

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.

Affected products

• Canonical Ubuntu Linux: 14.04, 16.04, 18.04
• Xkbcommon Libxkbcommon: before 0.8.1 — fixed in 0.8.1
• Xkbcommon: before 0.8.1 — fixed in 0.8.1

How to fix

Upgrade to a fixed version: Xkbcommon Libxkbcommon 0.8.1; Xkbcommon 0.8.1. Check the vendor advisory for mitigations.

References

• https://access.redhat.com/errata/RHSA-2019:2079
• https://github.com/xkbcommon/libxkbcommon/commit/1f9d1248c07cda8aaff762429c0dce146de8632a
• https://lists.freedesktop.org/archives/wayland-devel/2018-August/039232.html
• https://security.gentoo.org/glsa/201810-05
• https://usn.ubuntu.com/3786-1/
• https://usn.ubuntu.com/3786-2/
• https://access.redhat.com/errata/RHSA-2019:2079
• https://github.com/xkbcommon/libxkbcommon/commit/1f9d1248c07cda8aaff762429c0dce146de8632a
• https://lists.freedesktop.org/archives/wayland-devel/2018-August/039232.html
• https://security.gentoo.org/glsa/201810-05
• https://usn.ubuntu.com/3786-1/
• https://usn.ubuntu.com/3786-2/

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