Affects widely used Mozilla products; sandbox escape with CVSS 10.0 can lead to widespread host compromise and is newsworthy.
CVE-2026-16367
Browser sandbox escape in Disability Access APIs affecting Firefox/Thunderbird
Is CVE-2026-16367 being exploited?
Not confirmed. CVE-2026-16367 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.38% probability of exploitation in the next 30 days.
How severe is CVE-2026-16367?
CVE-2026-16367 is rated Critical with a CVSS score of 10.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-16367?
Yes. A fix has been recorded for CVE-2026-16367. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-16367 affect?
CVE-2026-16367 affects Mozilla Firefox <= 152 (fixed in 153), Mozilla Thunderbird <= 152 (fixed in 153). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-16367?
Update Firefox and Thunderbird to 153+ immediately
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Sandbox escape enabling arbitrary code execution on host via crafted content in Disability Access APIs, full system compromise possible.
Immediate action required