CVE-2026-84144 Affecting firefox package, versions <155.0-1
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.
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Test your applications- Snyk IDSNYK-DEBIANUNSTABLE-FIREFOX-19477588
- published2 Sept 2026
- disclosed1 Sept 2026
Introduced: 1 Sep 2026
NewCVE-2026-84144 (opens in a new tab)How to fix?
Upgrade Debian:unstable firefox to version 155.0-1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream firefox package and not the firefox package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
Internally found bugs present in Thunderbird 154 and Thunderbird ESR 153.1. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
References
- https://security-tracker.debian.org/tracker/CVE-2026-84144
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=2054619%2C2054620%2C2054624%2C2054702%2C2054726%2C2054775%2C2055703%2C2058006%2C2058013%2C2058098%2C2058627%2C2058661%2C2059127%2C2059128%2C2059180%2C2059199%2C2059205%2C2061320%2C2061430%2C2061495%2C2061505%2C2061532%2C2061799
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=2054625%2C2059002%2C2061775
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=2054691%2C2058085%2C2059144%2C2059191%2C2059192%2C2061521%2C2062395%2C2062404
- https://www.mozilla.org/security/advisories/mfsa2026-82/
- https://www.mozilla.org/security/advisories/mfsa2026-85/
- https://www.mozilla.org/security/advisories/mfsa2026-86/
- https://www.mozilla.org/security/advisories/mfsa2026-88/