Buffer Overflow Vulnerability in Thunderbird by Mozilla

CVE-2026-84640

What is CVE-2026-84640?

An issue in Thunderbird allows a maliciously crafted mail header to cause a buffer overflow. This could lead to unauthorized memory access, potentially allowing attackers to read past the end of a buffer. The vulnerability has been addressed in versions 155, 140.15, and 153.2, enhancing the security of the email client.

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