| Name | CVE-2026-100815 |
| Description | Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157. |
| 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-4814-1, DSA-6533-1 |
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, sid | 153.5.0esr-1 | fixed |
| thunderbird (PTS) | bookworm | 1:140.12.0esr-1~deb12u1 | fixed |
| bookworm (security) | 1:140.17.0esr-1~deb12u1 | fixed |
| trixie | 1:140.12.0esr-1~deb13u1 | fixed |
| trixie (security) | 1:140.17.0esr-1~deb13u1 | fixed |
| forky | 1:153.4.0esr-1 | fixed |
| sid | 1:153.5.0esr-1 | fixed |
The information below is based on the following data on fixed versions.
Notes
[trixie] - thunderbird <not-affected> (Vulnerable code not present, doesn't affect ESR140)
[bookworm] - thunderbird <not-affected> (Vulnerable code not present, doesn't affect ESR140)
https://www.mozilla.org/en-US/security/advisories/mfsa2026-97/#CVE-2026-100815
https://www.mozilla.org/en-US/security/advisories/mfsa2026-100/#CVE-2026-100815
https://www.mozilla.org/en-US/security/advisories/mfsa2026-103/#CVE-2026-100815