CVE-2025-4091
8.1
HIGH
CVSS 3.1
EPSS 0.32%
Description
Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. 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 138, Firefox ESR 128.10, Thunderbird 138, and Thunderbird 128.10.
How to fix CVE-2025-4091
To remediate CVE-2025-4091, upgrade the affected package to a fixed version below.
- —upgrade to 128.10.1esr-1~deb11u1 or later
- —upgrade to 1:128.10.1esr-1~deb11u1 or later
Is CVE-2025-4091 being exploited?
Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 128.10.1esr-1~deb11u1
- from 0, < 1:128.10.1esr-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 |