CVE-2025-5272

Memory safety bugs fixed in Firefox 139 and Thunderbird 139

State: Published
Severity: 7.3 High
Published: May 27, 2025
Updated: Apr 13, 2026
Reserved: May 27, 2025

Description

Memory safety bugs present in Firefox 138 and Thunderbird 138. 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 was fixed in Firefox 139 and Thunderbird 139.

Scores

CVSS	Score	Vector	Source
3.1	7.3 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L	CISA-ADP

Weaknesses

CWE-787 Out-of-bounds Write

Affected Products

Product	Versions
FirefoxMozilla	139 and laterNot affected
ThunderbirdMozilla	139 and laterNot affected

References

Memory safety bugs fixed in Firefox 139 and Thunderbird 139
https://www.mozilla.org/security/advisories/mfsa2025-42/
https://www.mozilla.org/security/advisories/mfsa2025-45/

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