What is CVE-2026-16367?

CVE-2026-16367 is a critical-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 10.0/10. Published 2026-07-21.

How severe is CVE-2026-16367?

Critical severity. CVSS v3 base score is 10.0 out of 10.

Buffer overflow in Mozilla Firefox

CVE-2026-16367

Sandbox escape due to invalid pointer in the Disability Access APIs component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

Vulnerability class: Buffer Overflow

EPSS: 0.004 (30.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

Affected products

Mozilla Firefox — versions 153
Mozilla Thunderbird — versions 153

Weakness classification (CWE)

References

security@mozilla.org (Permissions Required)
security@mozilla.org (Vendor Advisory)
security@mozilla.org (Vendor Advisory)

Frequently asked questions

What is CVE-2026-16367?: CVE-2026-16367 is a critical-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 10.0/10. Published 2026-07-21.
How severe is CVE-2026-16367?: Critical severity. CVSS v3 base score is 10.0 out of 10.