CVE-2026-8974
Thunderbird memory safety bugs may allow arbitrary code execution.
Is CVE-2026-8974 being exploited?
Not confirmed. CVE-2026-8974 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 0.33% probability of exploitation in the next 30 days.
How severe is CVE-2026-8974?
CVE-2026-8974 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-2026-8974?
Yes. A fix has been recorded for CVE-2026-8974. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-8974 affect?
CVE-2026-8974 affects Thunderbird 140.10, Thunderbird 150. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-8974?
Upgrade to Thunderbird 151 or ESR 140.11
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution via memory corruption in Thunderbird; could run arbitrary code via crafted mail content or attachments.
Immediate action required