PT-2026-63484 · Mozilla · Thunderbird

CVE-2026-14899

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Published

2026-07-22

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Updated

2026-07-22

None

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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.
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Related Identifiers

CVE-2026-14899

Affected Products

Thunderbird