CVE-2026-0891
8.1
HIGH
CVSS 3.1
EPSS 0.03%
Description
Memory safety bugs present in Firefox ESR 140.6, Thunderbird ESR 140.6, Firefox 146 and Thunderbird 146. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
How to fix CVE-2026-0891
To remediate CVE-2026-0891, upgrade the affected package to a fixed version below.
- —upgrade to 140.7.0esr-1~deb11u1 or later
- —upgrade to 1:140.7.0esr-1~deb11u1 or later
Is CVE-2026-0891 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 140.7.0esr-1~deb11u1
- from 0, < 1:140.7.0esr-1~deb11u1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |