Mozilla developers reported memory safety bugs present in Firefox 82.

published 2020-12-09 5y ago modified 2026-06-17 4mo ago also EUVD-2020-19493

cvss: 8.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.2%; EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits: 0; none known

Mozilla developers reported memory safety bugs present in Firefox 82. 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 < 83.

Patch / fix

fixed in 1 distros 4

mozilla firefox 83.0

ubuntu opensuse alpine arch linux

firefox Ubuntu 16.04 LTS 83.0+build2-0ubuntu0.16.04.3
firefox Ubuntu 18.04 LTS 83.0+build2-0ubuntu0.18.04.2
firefox Ubuntu 20.04 LTS 83.0+build2-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2020-26969

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 92.0-1.2

opensuse advisories openSUSE-SU-2024:14572-1 openSUSE-SU-2024:10600-1

firefox Alpine 3.23, Alpine 3.22, Alpine 3.21 +9 more 83.0-r0
librewolf Alpine 3.24, Alpine 3.23, Alpine 3.22 +1 more 83.0-r0

alpine advisories ALPINE-CVE-2020-26969

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

firefox Arch Linux 83.0-1

arch linux advisories AVG-1279

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Exploit prediction

1.22% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-09).

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
NVD	2.0	9.3	AV:N/AC:M/Au:N/C:C/I:C/A:C

Affected products

Mozilla Firefox

Classification

Weakness

CWE-787 Out-of-bounds Write

References

mozilla.org /security/advisories/mfsa2020-50/
vendor-advisory
bugzilla.mozilla.org /buglist.cgi?bug_id=1623920%2C1651705%2C1667872%2C1668876
broken-link

Sources

CVE List CVE-2020-26969
NVD CVE-2020-26969

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