Use-after-free in Mozilla products - CVE-2026-74940
Published: August 18, 2026
Vulnerability identifier: #VU144048
CSH Severity: High
CVSS v4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-74940
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to use-after-free in the Graphics: Text component when rendering content. A remote attacker can cause the browser to process crafted content to execute arbitrary code.
Affected software
Mozilla Firefox
Firefox ESR
Firefox for Android
Firefox ESR
Firefox for Android
How to mitigate CVE-2026-74940
Install security update from vendor's website.
Mozilla Firefox - update to 154.0
Firefox for Android - update to 154.0
Firefox ESR - addressed in versions 115.39.0, 140.14.0, 153.1.0
Firefox for Android - update to 154.0
Firefox ESR - addressed in versions 115.39.0, 140.14.0, 153.1.0
External References
- https://www.mozilla.org/en-US/security/advisories/mfsa2026-75/
- https://www.mozilla.org/en-US/security/advisories/mfsa2026-77/
- https://www.mozilla.org/en-US/security/advisories/mfsa2026-76/
- https://www.mozilla.org/en-US/security/advisories/mfsa2026-74/
- https://bugzilla.mozilla.org/show_bug.cgi?id=2054842