| Name | CVE-2026-6766 |
| 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. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | DLA-4546-1, DLA-4549-1, DSA-6225-1, DSA-6229-1, DSA-6290-1 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| firefox (PTS) | sid | 151.0.1-1 | fixed |
| firefox-esr (PTS) | bullseye | 115.14.0esr-1~deb11u1 | vulnerable |
| bullseye (security) | 140.11.0esr-1~deb11u1 | fixed | |
| bookworm | 140.10.2esr-1~deb12u1 | fixed | |
| bookworm (security) | 140.11.0esr-1~deb12u1 | fixed | |
| trixie | 140.10.2esr-1~deb13u1 | fixed | |
| trixie (security) | 140.11.0esr-1~deb13u1 | fixed | |
| forky | 140.10.2esr-1 | fixed | |
| sid | 140.11.0esr-1 | fixed | |
| nss (PTS) | bullseye | 2:3.61-1+deb11u3 | vulnerable |
| bullseye (security) | 2:3.61-1+deb11u5 | vulnerable | |
| bookworm, bookworm (security) | 2:3.87.1-1+deb12u2 | vulnerable | |
| trixie | 2:3.110-1+deb13u1 | vulnerable | |
| trixie (security) | 2:3.110-1+deb13u2 | fixed | |
| forky | 2:3.123.1-1 | fixed | |
| sid | 2:3.124-1 | fixed | |
| thunderbird (PTS) | bullseye | 1:115.12.0-1~deb11u1 | vulnerable |
| bullseye (security) | 1:140.11.0esr-1~deb11u1 | fixed | |
| bookworm | 1:140.10.1esr-1~deb12u1 | fixed | |
| bookworm (security) | 1:140.11.0esr-1~deb12u1 | fixed | |
| trixie | 1:140.10.1esr-1~deb13u1 | fixed | |
| trixie (security) | 1:140.11.0esr-1~deb13u1 | fixed | |
| forky | 1:140.10.2esr-1 | fixed | |
| sid | 1:140.11.0esr-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| firefox | source | (unstable) | 150.0-1 | |||
| firefox-esr | source | bullseye | 140.10.0esr-1~deb11u1 | DLA-4546-1 | ||
| firefox-esr | source | bookworm | 140.10.0esr-1~deb12u1 | DSA-6225-1 | ||
| firefox-esr | source | trixie | 140.10.0esr-1~deb13u1 | DSA-6225-1 | ||
| firefox-esr | source | (unstable) | 140.10.0esr-1 | |||
| nss | source | trixie | 2:3.110-1+deb13u2 | DSA-6290-1 | ||
| nss | source | (unstable) | 2:3.123-1 | |||
| thunderbird | source | bullseye | 1:140.10.0esr-1~deb11u1 | DLA-4549-1 | ||
| thunderbird | source | bookworm | 1:140.10.0esr-1~deb12u1 | DSA-6229-1 | ||
| thunderbird | source | trixie | 1:140.10.0esr-1~deb13u1 | DSA-6229-1 | ||
| thunderbird | source | (unstable) | 1:140.10.0esr-1 |
https://www.mozilla.org/en-US/security/advisories/mfsa2026-30/#CVE-2026-6766
https://www.mozilla.org/en-US/security/advisories/mfsa2026-32/#CVE-2026-6766
https://www.mozilla.org/en-US/security/advisories/mfsa2026-34/#CVE-2026-6766
https://hg.mozilla.org/projects/nss/rev/42da9a7f8a03
Introduced by: https://hg-edge.mozilla.org/projects/nss/rev/e7c7f305078ea9c652e9af6f28af3c3eed36c8ab (NSS_3_52_BETA1)