CVE-2026-12326
Memory safety bugs in Firefox 151/Thunderbird 151 may permit arbitrary code execution.
Is CVE-2026-12326 being exploited?
Not confirmed. CVE-2026-12326 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 0.36% probability of exploitation in the next 30 days.
How severe is CVE-2026-12326?
CVE-2026-12326 is rated High with a CVSS score of 8.1. 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-2026-12326?
Yes. A fix has been recorded for CVE-2026-12326. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-12326 affect?
CVE-2026-12326 affects Firefox 151, Thunderbird 151. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-12326?
Update to Firefox 152 and Thunderbird 152
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Arbitrary code execution via memory corruption in Firefox 151/Thunderbird 151; exploit may require effort.
Patch when possible