Memory Vulnerability in Mozilla Thunderbird by Mozilla

CVE-2026-84639

What is CVE-2026-84639?

In specific scenarios involving certain MIME body formats, triggering an error condition can lead to the use of uninitialized memory within Mozilla Thunderbird. This behavior may potentially allow an attacker to exploit the vulnerability, leading to unpredictable application behavior or unauthorized access to sensitive information. The issue has been addressed in several versions of Thunderbird, ensuring that users are protected from this type of memory misuse.

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