CVE-2025-0243 — Out-of-bounds Write in Mozilla Firefox

CWE-787 — Out-of-bounds WriteCWE-120 — Classic Buffer Overflow13 documents8 sources
Severity
5.1MEDIUMNVD
OSV5.4
EPSS
0.0%
top 91.63%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla ThunderbirdMozilla Firefox
Timeline
PublishedJan 7
Latest updateFeb 2

Description

Memory safety bugs present in Firefox 133, Thunderbird 133, Firefox ESR 128.5, and Thunderbird 128.5. 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 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:NExploitability: 2.5 | Impact: 2.5

Affected Packages4 packages

▶NVDmozilla/firefox< 128.6.0+1
▶NVDmozilla/thunderbird129.0 — 134.0+1
▶Ubuntumozilla/firefox< 134.0+build1-0ubuntu0.20.04.1
▶Debianmozilla/thunderbird< 1:128.6.0esr-1~deb11u1+3

🔴Vulnerability Details

4
OSV
firefox vulnerabilities↗2025-01-09
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CVEList
Memory safety bugs fixed in Firefox 134, Thunderbird 134, Firefox ESR 128.6, and Thunderbird 128.6↗2025-01-07
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GHSA
GHSA-928f-3rxq-5jvp: Memory safety bugs present in Firefox 133, Thunderbird 133, Firefox ESR 128↗2025-01-07
▶
OSV
CVE-2025-0243: Memory safety bugs present in Firefox 133, Thunderbird 133, Firefox ESR 128↗2025-01-07
▶

📋Vendor Advisories

8
Ubuntu
Thunderbird vulnerabilities↗2026-02-02
▶
Ubuntu
Firefox vulnerabilities↗2025-01-09
▶
Red Hat
firefox: thunderbird: Memory safety bugs fixed in Firefox 134, Thunderbird 134, Firefox ESR 128.6, and Thunderbird 128.6↗2025-01-07
▶
Debian
CVE-2025-0243: firefox - Memory safety bugs present in Firefox 133, Thunderbird 133, Firefox ESR 128.5, a...↗2025
▶
Mozilla
Mozilla Foundation Security Advisory 2025-05: CVE-2025-0243↗
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CVE-2025-0243 — Out-of-bounds Write in Mozilla Firefox | cvebase