CVE-2026-100821 Affecting thunderbird package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-UBUNTU2204-THUNDERBIRD-20339057
- published1 Oct 2026
- disclosed29 Sept 2026
Introduced: 29 Sep 2026
NewCVE-2026-100821 (opens in a new tab)How to fix?
There is no fixed version for Ubuntu:22.04 thunderbird.
NVD Description
Note: Versions mentioned in the description apply only to the upstream thunderbird package and not the thunderbird package as distributed by Ubuntu.
See How to fix? for Ubuntu:22.04 relevant fixed versions and status.
Site isolation issue in the Panning and Zooming component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
References
- http://people.ubuntu.com/~ubuntu-security/cve/CVE-2026-100821
- https://bugzilla.mozilla.org/show_bug.cgi?id=2071784
- https://www.mozilla.org/security/advisories/mfsa2026-100/
- https://www.mozilla.org/security/advisories/mfsa2026-97/
- https://www.mozilla.org/security/advisories/mfsa2026-98/
- https://www.mozilla.org/security/advisories/mfsa2026-99/
- https://www.mozilla.org/security/advisories/mfsa2026-101/
- https://www.mozilla.org/security/advisories/mfsa2026-102/
- https://www.mozilla.org/security/advisories/mfsa2026-103/