This page tracks the Debian fix status. The vulnerability itself is described on the main CVE page. View CVE-2026-14899 →

DEBIAN-CVE-2026-14899

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, allowin...

Original description

The description as published by the source.

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: OSV.dev (Open Source Vulnerabilities) OSV

Affected packages

Debian:12 thunderbird

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:140.13.0esr-2~deb12u1"}]}]

Debian:13 thunderbird

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:140.13.0esr-2~deb13u1"}]}]

Debian:14 thunderbird

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:140.13.0esr-1"}]}]

References

advisory security-tracker.debian.org