Memory safety bugs fixed in Firefox 109

published 2023-06-02 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-27706

cvss: 8.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits: 0; none known

Mozilla developers and the Mozilla Fuzzing Team reported memory safety bugs present in Firefox 108. 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 < 109.

Patch / fix

fixed in 1 distros 2

Mozilla Firefox 109

ubuntu opensuse

firefox Ubuntu 18.04 LTS 109.0+build2-0ubuntu0.18.04.1
firefox Ubuntu 20.04 LTS 109.0+build2-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2023-23606

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 109.0-1.1

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:12623-1

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 21 mo ago (2025-01-10)

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

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

bugzilla.mozilla.org /buglist.cgi?bug_id=1764974%2C1798591%2C1799201%2C1800446%2C1801248%2C1802100%2C1803393%2C1804626%2C1804971%2C
issue-tracking, vendor-advisory
mozilla.org /security/advisories/mfsa2023-01/
vendor-advisory

Sources

CVE List CVE-2023-23606
NVD CVE-2023-23606

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