Memory safety bugs present in Firefox 118.

published 2023-10-24 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-58017

cvss: 9.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.1%; EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits: 0; none known

Memory safety bugs present in Firefox 118. 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 < 119.

Patch / fix

fixed in 1 distros 4

Mozilla Firefox 119

ubuntu suse opensuse alpine

firefox Ubuntu 20.04 LTS 119.0+build2-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2023-5731

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

MozillaFirefox SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +9 more 115.4.0-150200.152.114.1
MozillaFirefox SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 115.4.0-112.188.1
MozillaFirefox SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLE High Performance Computing 15 SP1-LTSS 115.4.0-150000.150.113.1

suse advisories SUSE-SU-2023:4214-1 SUSE-SU-2023:4213-1 SUSE-SU-2023:4212-1

firefox-esr openSUSE Tumbleweed 128.5.1-1.1
MozillaFirefox openSUSE Tumbleweed 119.0-1.1

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:13385-1

firefox Alpine 3.23, Alpine 3.22, Alpine 3.21 +3 more 119.0-r0
librewolf Alpine 3.24, Alpine 3.23, Alpine 3.22 119.0-r0

alpine advisories ALPINE-CVE-2023-5731

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

Exploit prediction

1.15% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Mozilla Firefox

Classification

Weakness

CWE-787 Out-of-bounds Write

References

bugzilla.mozilla.org /buglist.cgi?bug_id=1690111%2C1721904%2C1851803%2C1854068
issue-tracking, vendor-advisory
mozilla.org /security/advisories/mfsa2023-45/
vendor-advisory
security.gentoo.org /glsa/202401-10

Sources

CVE List CVE-2023-5731
NVD CVE-2023-5731

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