| Name | CVE-2026-14899 |
| Description | The code to parse MIME headers for display when forwarding a message (if the setting to view all headers was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer for the headers, and potentially crashing Thunderbird. This vulnerability was fixed in Thunderbird 153 and Thunderbird 140.13. |
| 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-4727-1, DSA-6418-1 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| thunderbird (PTS) | bullseye | 1:115.12.0-1~deb11u1 | vulnerable |
| bullseye (security) | 1:140.13.0esr-2~deb11u1 | fixed | |
| bookworm | 1:140.12.0esr-1~deb12u1 | vulnerable | |
| bookworm (security) | 1:140.13.0esr-2~deb12u1 | fixed | |
| trixie | 1:140.12.0esr-1~deb13u1 | vulnerable | |
| trixie (security) | 1:140.13.0esr-2~deb13u1 | fixed | |
| forky, sid | 1:140.13.0esr-2 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| thunderbird | source | bullseye | 1:140.13.0esr-2~deb11u1 | DLA-4727-1 | ||
| thunderbird | source | bookworm | 1:140.13.0esr-2~deb12u1 | DLA-4727-1 | ||
| thunderbird | source | trixie | 1:140.13.0esr-2~deb13u1 | DSA-6418-1 | ||
| thunderbird | source | (unstable) | 1:140.13.0esr-1 |
https://www.mozilla.org/en-US/security/advisories/mfsa2026-72/#CVE-2026-14899