What is CVE-2026-16359?

CVE-2026-16359 is a critical-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.1/10. Published 2026-07-21.

How severe is CVE-2026-16359?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Buffer overflow in Mozilla Firefox

CVE-2026-16359

Incorrect boundary conditions in the Audio/Video: GMP component. This vulnerability was fixed in Firefox 153, Firefox ESR 115.38, and Firefox ESR 140.13.

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

Affected products

Mozilla Firefox — versions 115.38, 140.13, 153

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

References

security@mozilla.org
security@mozilla.org
security@mozilla.org
security@mozilla.org

Frequently asked questions

What is CVE-2026-16359?: CVE-2026-16359 is a critical-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.1/10. Published 2026-07-21.
How severe is CVE-2026-16359?: Critical severity. CVSS v3 base score is 9.1 out of 10.