| Name | CVE-2026-4711 |
| Description | Use-after-free in the Widget: Cocoa component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9. |
| 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) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| firefox (PTS) | sid | 148.0.2-1 | fixed |
| firefox-esr (PTS) | bullseye | 115.14.0esr-1~deb11u1 | fixed |
| bullseye (security) | 140.8.0esr-1~deb11u1 | fixed |
| bookworm | 128.14.0esr-1~deb12u1 | fixed |
| bookworm (security) | 140.8.0esr-1~deb12u1 | fixed |
| trixie (security), trixie | 140.8.0esr-1~deb13u1 | fixed |
| forky | 140.8.0esr-1 | fixed |
| sid | 140.9.0esr-1 | fixed |
| thunderbird (PTS) | bullseye | 1:115.12.0-1~deb11u1 | fixed |
| bullseye (security) | 1:140.8.0esr-1~deb11u1 | fixed |
| bookworm | 1:140.6.0esr-1~deb12u1 | fixed |
| bookworm (security) | 1:140.8.0esr-1~deb12u1 | fixed |
| trixie (security), trixie | 1:140.8.0esr-1~deb13u1 | fixed |
| forky, sid | 1:140.8.0esr-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) | (not affected) | | | |
| firefox-esr | source | (unstable) | (not affected) | | | |
| thunderbird | source | (unstable) | (not affected) | | | |
Notes
- firefox <not-affected> (Only affects Firefox on MacOS)
- firefox-esr <not-affected> (Only affects Firefox ESR on MacOS)
- thunderbird <not-affected> (Only affects Thunderbird on MacOS)
https://www.mozilla.org/en-US/security/advisories/mfsa2026-20/#CVE-2026-4711
https://www.mozilla.org/en-US/security/advisories/mfsa2026-22/#CVE-2026-4711
https://www.mozilla.org/en-US/security/advisories/mfsa2026-24/#CVE-2026-4711