CVE-2026-16372
Firefox/Thunderbird DOM content-process privilege escalation allowing sandbox escape.
Is CVE-2026-16372 being exploited?
Not confirmed. CVE-2026-16372 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 0.30% probability of exploitation in the next 30 days.
How severe is CVE-2026-16372?
CVE-2026-16372 is rated Critical with a CVSS score of 9.8. 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-2026-16372?
Yes. A fix has been recorded for CVE-2026-16372. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-16372 affect?
CVE-2026-16372 affects Mozilla Firefox < 153, Mozilla Thunderbird < 153, Firefox Content Processes. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-16372?
Upgrade Firefox/Thunderbird to v153+ immediately on all endpoints.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Web content can escalate privileges by escaping the content sandbox, enabling access to browser‑level data or code execution in privileged process.
Immediate action required