| Name | CVE-2026-2784 |
| Description | Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8. |
| 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-4495-1, DLA-4496-1, DSA-6148-1, DSA-6152-1 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| firefox (PTS) | sid | 152.0.3-1 | fixed |
| firefox-esr (PTS) | bullseye | 115.14.0esr-1~deb11u1 | vulnerable |
| bullseye (security) | 140.12.0esr-1~deb11u1 | fixed |
| bookworm | 140.10.2esr-1~deb12u1 | fixed |
| bookworm (security) | 140.12.0esr-1~deb12u1 | fixed |
| trixie | 140.10.2esr-1~deb13u1 | fixed |
| trixie (security) | 140.12.0esr-1~deb13u1 | fixed |
| forky, sid | 140.12.0esr-1 | fixed |
| thunderbird (PTS) | bullseye | 1:115.12.0-1~deb11u1 | vulnerable |
| bullseye (security) | 1:140.12.0esr-1~deb11u1 | fixed |
| bookworm | 1:140.10.1esr-1~deb12u1 | fixed |
| bookworm (security) | 1:140.12.0esr-1~deb12u1 | fixed |
| trixie | 1:140.10.1esr-1~deb13u1 | fixed |
| trixie (security) | 1:140.12.0esr-1~deb13u1 | fixed |
| forky, sid | 1:140.12.0esr-1 | fixed |
The information below is based on the following data on fixed versions.
Notes
https://www.mozilla.org/en-US/security/advisories/mfsa2026-13/#CVE-2026-2784
https://www.mozilla.org/en-US/security/advisories/mfsa2026-15/#CVE-2026-2784
https://www.mozilla.org/en-US/security/advisories/mfsa2026-17/#CVE-2026-2784
