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Appaloosa Scout

Vulnerability · NVD

CVE-2026-14899

HIGH 7.5

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.

Attack vector : Network No privileges required No user interaction
Show raw CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS 0.26% exploit very unlikely percentile 17.6%

Tracked apps referencing this CVE

For each app: the affected range, the fixing version, and where the tracked app stands today.

Vulnerable CPE configurations (1)
Vendor Product Versions
mozilla thunderbird
All platforms (wildcard)
<140.13.0
View on NVD ↗ Advisory · www.mozilla.org