CVE-2026-74944
Use-after-free in Firefox/Thunderbird DOM enabling remote code execution.
Is CVE-2026-74944 being exploited?
Not confirmed. CVE-2026-74944 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 0.40% probability of exploitation in the next 30 days.
How severe is CVE-2026-74944?
CVE-2026-74944 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-2026-74944?
Yes. A fix has been recorded for CVE-2026-74944. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-74944 affect?
CVE-2026-74944 affects Mozilla Firefox before 154, Firefox ESR before 140.14 and 153.1, Mozilla Thunderbird before 154, Thunderbird ESR before 140.14 and 153.1. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-74944?
Update Firefox and Thunderbird to the listed fixed versions immediately.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution via crafted web/email content; attacker can run arbitrary code in the user context and exfiltrate data or install malware.
Immediate action required