CVE-2026-8958
8.6
HIGH
CVSS 3.1
EPSS 0.06%
Description
Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
How to fix CVE-2026-8958
To remediate CVE-2026-8958, upgrade the affected package to a fixed version below.
- Debian/firefox-esr—upgrade to 140.11.0esr-1~deb11u1 or later
- Debian/thunderbird—upgrade to 1:140.11.0esr-1~deb11u1 or later
Is CVE-2026-8958 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 140.11.0esr-1~deb11u1
- from 0, < 1:140.11.0esr-1~deb11u1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N |