| Name | CVE-2026-100778 |
| Description | Sandbox escape due to use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. |
| 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-4810-1, DLA-4814-1, DSA-6533-1, DSA-6536-1 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| firefox (PTS) | sid | 157.0-1 | fixed |
| firefox-esr (PTS) | bookworm | 140.12.0esr-1~deb12u1 | vulnerable |
| bookworm (security) | 153.4.0esr-1~deb12u1 | fixed | |
| trixie | 140.15.0esr-1~deb13u1 | vulnerable | |
| trixie (security) | 153.4.0esr-1~deb13u1 | fixed | |
| forky | 140.16.0esr-1 | vulnerable | |
| sid | 153.4.0esr-1 | fixed | |
| thunderbird (PTS) | bookworm | 1:140.12.0esr-1~deb12u1 | vulnerable |
| bookworm (security) | 1:140.17.0esr-1~deb12u1 | fixed | |
| trixie | 1:140.12.0esr-1~deb13u1 | vulnerable | |
| trixie (security) | 1:140.17.0esr-1~deb13u1 | fixed | |
| forky | 1:140.14.0esr-1 | vulnerable | |
| sid | 1:153.4.0esr-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) | 157.0-1 | |||
| firefox-esr | source | bookworm | 153.4.0esr-1~deb12u1 | DLA-4814-1 | ||
| firefox-esr | source | trixie | 153.4.0esr-1~deb13u1 | DSA-6533-1 | ||
| firefox-esr | source | (unstable) | 153.4.0esr-1 | |||
| thunderbird | source | bookworm | 1:140.17.0esr-1~deb12u1 | DLA-4810-1 | ||
| thunderbird | source | trixie | 1:140.17.0esr-1~deb13u1 | DSA-6536-1 | ||
| thunderbird | source | (unstable) | 1:153.4.0esr-1 |
https://www.mozilla.org/en-US/security/advisories/mfsa2026-97/#CVE-2026-100778
https://www.mozilla.org/en-US/security/advisories/mfsa2026-100/#CVE-2026-100778
https://www.mozilla.org/en-US/security/advisories/mfsa2026-103/#CVE-2026-100778