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Fencer Vulns
high 8.8

CVE-2023-6873 json

Memory safety bugs present in Firefox 120.

published 2023-12-19 2 y ago modified 2026-06-17 4 mo ago also EUVD-2023-59077

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

Memory safety bugs present in Firefox 120. 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 < 121.

Patch / fix

  • Mozilla Firefox 121
  • thunderbird Debian 12 1:115.6.0-1~deb12u1

debian advisories DEBIAN-CVE-2023-6873

  • firefox Ubuntu 20.04 LTS 121.0+build1-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2023-6873

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 121.0-1.1

opensuse advisories openSUSE-SU-2024:14572-1openSUSE-SU-2024:13531-1

Exploit prediction

0.85% chance of exploitation in the next 30 days, higher than 58% 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

References

Sources

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.