Mozilla Thunderbird vulnerabilities: known CVEs & security history
Mozilla · Email client · 167 tracked CVEs · 0 actively exploited · updated August 2026 · what is a CVE? →
This is the full list of known vulnerabilities (CVEs) across all Mozilla Thunderbird release lines — 167 in total. A CVE here doesn't mean your version is affected — check Mozilla Thunderbird's current status and the safe version to run.
Known Mozilla Thunderbird CVEs
Actively-exploited and most-severe first. Showing the top 80 of 167. Open any CVE for full details.
| CVE | Severity | CVSS | EPSS | Year |
|---|---|---|---|---|
| CVE-2026-16367 | critical | 10 | 0% | 2026 |
| CVE-2026-4692 | critical | 10 | 0% | 2026 |
| CVE-2026-4689 | critical | 10 | 1% | 2026 |
| CVE-2026-2778 | critical | 10 | 0% | 2026 |
| CVE-2026-2776 | critical | 10 | 0% | 2026 |
| CVE-2026-2768 | critical | 10 | 0% | 2026 |
| CVE-2026-2761 | critical | 10 | 0% | 2026 |
| CVE-2026-2760 | critical | 10 | 0% | 2026 |
| CVE-2026-0881 | critical | 10 | 0% | 2026 |
| CVE-2026-16410 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16407 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16402 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16389 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16388 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16387 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16383 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16382 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16377 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16375 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16369 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16368 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16363 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16361 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16360 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16358 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16357 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16356 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16355 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16353 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16352 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16351 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16350 | critical | 9.8 | 0% | 2026 |
| CVE-2026-16349 | critical | 9.8 | 0% | 2026 |
| CVE-2026-12293 | critical | 9.8 | 0% | 2026 |
| CVE-2026-8094 | critical | 9.8 | 0% | 2026 |
| CVE-2026-8091 | critical | 9.8 | 0% | 2026 |
| CVE-2026-6748 | critical | 9.8 | 0% | 2026 |
| CVE-2026-5735 | critical | 9.8 | 0% | 2026 |
| CVE-2026-5734 | critical | 9.8 | 0% | 2026 |
| CVE-2026-5731 | critical | 9.8 | 0% | 2026 |
| CVE-2026-4729 | critical | 9.8 | 0% | 2026 |
| CVE-2026-4721 | critical | 9.8 | 0% | 2026 |
| CVE-2026-4720 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2807 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2799 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2797 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2796 | critical | 9.8 | 1% | 2026 |
| CVE-2026-2795 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2793 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2792 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2777 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2775 | critical | 9.8 | 1% | 2026 |
| CVE-2026-2774 | critical | 9.8 | 1% | 2026 |
| CVE-2026-2773 | critical | 9.8 | 1% | 2026 |
| CVE-2026-2772 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2771 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2770 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2767 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2766 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2765 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2764 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2763 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2762 | critical | 9.8 | 1% | 2026 |
| CVE-2026-2759 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2758 | critical | 9.8 | 0% | 2026 |
| CVE-2026-2757 | critical | 9.8 | 0% | 2026 |
| CVE-2026-0879 | critical | 9.8 | 1% | 2026 |
| CVE-2026-12297 | critical | 9.6 | 0% | 2026 |
| CVE-2026-12296 | critical | 9.6 | 0% | 2026 |
| CVE-2026-12295 | critical | 9.6 | 0% | 2026 |
| CVE-2026-12294 | critical | 9.6 | 0% | 2026 |
| CVE-2026-16393 | critical | 9.1 | 0% | 2026 |
| CVE-2026-16390 | critical | 9.1 | 0% | 2026 |
| CVE-2026-16381 | critical | 9.1 | 0% | 2026 |
| CVE-2026-16380 | critical | 9.1 | 0% | 2026 |
| CVE-2026-16370 | critical | 9.1 | 0% | 2026 |
| CVE-2026-16364 | critical | 9.1 | 0% | 2026 |
| CVE-2026-16359 | critical | 9.1 | 0% | 2026 |
| CVE-2026-8948 | critical | 9.1 | 0% | 2026 |
| CVE-2026-16401 | high | 8.8 | 0% | 2026 |
87 older / lower-severity CVEs not shown — see Mozilla Thunderbird's full record.
Is my Mozilla Thunderbird version affected?
The list above spans every release. To know whether your version is affected — and the minimum safe version to upgrade to — check it directly.
Check your Mozilla Thunderbird version → · Monitor Mozilla Thunderbird for new CVEs →
Mozilla Thunderbird vulnerabilities — frequently asked
How many known vulnerabilities does Mozilla Thunderbird have?
IsItPatched tracks 167 CVEs for Mozilla Thunderbird. 79 are critical-severity and 74 high-severity. These span every release line — what matters is whether the version you run is affected.
Does Mozilla Thunderbird have any actively-exploited vulnerabilities?
None of Mozilla Thunderbird's tracked CVEs are currently in CISA's KEV catalog — but new ones can be added at any time, so keep your version current.
What is the most severe Mozilla Thunderbird vulnerability?
Among tracked issues, CVE-2026-16367 (CRITICAL, CVSS 10) ranks highest — a Memory corruption weakness.
Is Mozilla Thunderbird safe to use?
It depends on the version. The latest supported Mozilla Thunderbird release clears the known issues; older versions may still be affected. Check the exact version you run for a verdict.
CVE data aggregated from NVD, CISA KEV and EPSS (FIRST.org). Related: Mozilla Thunderbird security status · Mozilla Thunderbird end-of-life · actively-exploited CVEs. Always verify against Mozilla's advisories — see our disclaimer.