CVE-2025-5272 — Out-of-bounds Write in Mozilla Firefox

CWE-787 — Out-of-bounds WriteCWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer9 documents8 sources
Severity
7.3HIGHNVD
EPSS
0.4%
top 41.33%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla FirefoxMozilla Thunderbird
Timeline
PublishedMay 27
Latest updateFeb 2

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:LExploitability: 3.9 | Impact: 3.4

Affected Packages3 packages

▶NVDmozilla/firefox< 139.0
▶NVDmozilla/thunderbird< 139.0
▶Ubuntumozilla/thunderbird< 1:140.7.1+build1-0ubuntu0.22.04.1

🔴Vulnerability Details

3
GHSA
GHSA-h36q-jch3-f9mw: Memory safety bugs present in Firefox 138 and Thunderbird 138↗2025-05-27
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OSV
CVE-2025-5272: Memory safety bugs present in Firefox 138 and Thunderbird 138↗2025-05-27
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CVEList
Memory safety bugs fixed in Firefox 139 and Thunderbird 139↗2025-05-27
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📋Vendor Advisories

5
Ubuntu
Thunderbird vulnerabilities↗2026-02-02
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Red Hat
firefox: Memory safety bugs↗2025-05-27
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Debian
CVE-2025-5272: firefox - Memory safety bugs present in Firefox 138 and Thunderbird 138. Some of these bug...↗2025
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Mozilla
Mozilla Foundation Security Advisory 2025-45: CVE-2025-5272↗
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Mozilla
Mozilla Foundation Security Advisory 2025-42: CVE-2025-5272↗
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CVE-2025-5272 — Out-of-bounds Write in Mozilla Firefox | cvebase