CVE-2025-11721 | Memory safety bug present in Firefox 143 and Thunderbird 143… | CVSS 9.8 CRITICAL

Description

Memory safety bug present in Firefox 143 and Thunderbird 143. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 144 and Thunderbird 144.

Metadata

CVE ID: CVE-2025-11721
State: PUBLISHED
Assigner: mozilla
Reserved: 2025-10-13 19:50 UTC
Published: 2025-10-14 12:27 UTC
Last updated: 2026-04-13 14:31 UTC
Primary CWE: CWE-119
CWE-119 Improper Restriction of Operations within the Bounds…
Vendor / Product: Mozilla / Firefox
Sources: cve.org · NVD

Severity & Metrics

9.8 CRITICAL CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: total

Affected products (2)

Vendor	Product	Platform	Versions
Mozilla	Firefox	—	144 ≤ *
Mozilla	Thunderbird	—	144 ≤ *

Weakness (CWE)

CWE	Source	Description
CWE-119	adp	CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

CVSS scores (1)

Score	Severity	Version	Source	Vector
9.8	CRITICAL	3.1	adp	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References (3)

Memory safety bug fixed in Firefox 144 and Thunderbird 144 https://bugzilla.mozilla.org/show_bug.cgi?id=1986816
https://www.mozilla.org/security/advisories/mfsa2025-81/
https://www.mozilla.org/security/advisories/mfsa2025-84/