| Name | CVE-2026-109751 |
| Description | Information disclosure in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5. |
| 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-4836-1, DSA-6560-1 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| firefox (PTS) | sid | 158.0-1 | fixed |
| firefox-esr (PTS) | bookworm | 140.12.0esr-1~deb12u1 | vulnerable |
| bookworm (security) | 153.5.0esr-1~deb12u1 | fixed |
| trixie | 140.15.0esr-1~deb13u1 | vulnerable |
| trixie (security) | 153.5.0esr-1~deb13u1 | fixed |
| forky | 153.4.0esr-1 | vulnerable |
| sid | 153.5.0esr-1 | fixed |
| thunderbird (PTS) | bookworm | 1:140.12.0esr-1~deb12u1 | vulnerable |
| bookworm (security) | 1:140.17.0esr-1~deb12u1 | vulnerable |
| trixie | 1:140.12.0esr-1~deb13u1 | vulnerable |
| trixie (security) | 1:140.17.0esr-1~deb13u1 | vulnerable |
| forky | 1:153.4.0esr-1 | vulnerable |
| sid | 1:153.5.0esr-1 | fixed |
The information below is based on the following data on fixed versions.
Notes
https://www.mozilla.org/en-US/security/advisories/mfsa2026-106/#CVE-2026-109751
https://www.mozilla.org/en-US/security/advisories/mfsa2026-108/#CVE-2026-109751
https://www.mozilla.org/en-US/security/advisories/mfsa2026-109/#CVE-2026-109751