CVE-2026-6766
7.5
HIGH
CVSS 3.1
EPSS 0.05%
Description
Incorrect boundary conditions in the Libraries component in NSS. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
How to fix CVE-2026-6766
To remediate CVE-2026-6766, upgrade the affected package to a fixed version below.
- Debian/firefox-esr—upgrade to 140.10.0esr-1~deb11u1 or later
- Debian/nss—no fix listed
- —upgrade to 1:140.10.0esr-1~deb11u1 or later
Is CVE-2026-6766 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 140.10.0esr-1~deb11u1
- from 0
- from 0, < 1:140.10.0esr-1~deb11u1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |