Memory safety bugs present in Firefox 119.

published 2023-11-21 2 y ago modified 2026-06-17 4 mo ago also EUVD-2023-58460

cvss: 8.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.7%; EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits: 0; none known

Memory safety bugs present in Firefox 119. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 120.

Patch / fix

fixed in 1 distros 2

Mozilla Firefox 120

ubuntu opensuse

firefox Ubuntu 20.04 LTS 120.0+build2-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2023-6213

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

firefox-esr openSUSE Tumbleweed 128.5.1-1.1
MozillaFirefox openSUSE Tumbleweed 120.0-1.1

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:13468-1

Exploit prediction

0.67% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

Mozilla Firefox

Classification

Weakness

CWE-787 Out-of-bounds Write

References

mozilla.org /security/advisories/mfsa2023-49/
release-notes, vendor-advisory
bugzilla.mozilla.org /buglist.cgi?bug_id=1849265%2C1851118%2C1854911
broken-link
security.gentoo.org /glsa/202401-10

Sources

CVE List CVE-2023-6213
NVD CVE-2023-6213

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