CVE-2026-8950
9.3
CRITICAL
CVSS 3.1
EPSS 0.02%
Description
Same-origin policy bypass in the Networking: HTTP component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
How to fix CVE-2026-8950
To remediate CVE-2026-8950, 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-2026-8950 being exploited?
Low — EPSS is 0.0%, 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 | CRITICAL9.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N |