CVE-2026-16367 — Firefox
CRITICALCVE-2026-16367 is a critical-severity (CVSS 10) Buffer Overflow vulnerability in mozilla firefox. A fix is available — see the affected versions and patch details below.
Sandbox escape due to invalid pointer in the Disability Access APIs component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-16367.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-16367 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 380,526 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Description
Sandbox escape due to invalid pointer in the Disability Access APIs component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.
Affected Products
firefoxmozillathunderbirdmozillaDetection & mitigation playbook
Vendor / applianceDetect
Inventory every mozilla firefox deployment and check each version against the affected-products list above.
Fix
Apply the mozilla firefox security patch or hotfix for CVE-2026-16367 on the affected version, following the vendor advisory for your exact build.
Workarounds
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2026-16367 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.