WebKitGTK+ 2.20.3 has an off-by-one error, with a resultant out-of-bounds write, in the get_simple_globs functions in ThirdParty/xdgmime/sr…

published 2018-07-19 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-4864

cvss: 9.8; version 3.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.7%; EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits: 0; none known

WebKitGTK+ 2.20.3 has an off-by-one error, with a resultant out-of-bounds write, in the get_simple_globs functions in ThirdParty/xdgmime/src/xdgmimecache.c and ThirdParty/xdgmime/src/xdgmimeglob.c.

Patch / fix

distros 5 links 1

debian ubuntu suse opensuse alpine

webkit2gtk Debian 14, Debian 13, Debian 12 2.20.4-1

debian advisories DEBIAN-CVE-2018-12911

webkit2gtk Ubuntu 16.04 LTS 2.20.5-0ubuntu0.16.04.1
webkit2gtk Ubuntu 18.04 LTS 2.20.5-0ubuntu0.18.04.1

ubuntu advisories UBUNTU-CVE-2018-12911

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

webkit2gtk3 SLES for SAP 12 SP3, SLES 12 SP3, SLED 12 SP3 +2 more 2.20.3-2.23.8
webkit2gtk3 SLE Module for Desktop Applications 15, SLE Module for Basesystem 15 2.20.5-3.8.1

suse advisories SUSE-SU-2018:3387-1 SUSE-SU-2018:2752-1

gtk3 openSUSE Tumbleweed 2.32.4-1.1

opensuse advisories openSUSE-SU-2024:11506-1

webkit2gtk Alpine 3.8 2.20.4-r0

alpine advisories ALPINE-CVE-2018-12911

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

trac.webkit.org/changeset/233404/webkit advisory

Exploit prediction

1.73% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.0	9.8	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

CWE-787 Out-of-bounds Write

References

trac.webkit.org /changeset/233404/webkit
patch, vendor-advisory
usn.ubuntu.com /3743-1/
vendor-advisory, third-party-advisory

Sources

CVE List CVE-2018-12911
NVD CVE-2018-12911

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary