Email Client Vulnerability in Thunderbird by Mozilla

CVE-2026-118175

What is CVE-2026-118175?

A critical issue in Thunderbird enables the inadvertent disclosure of email content when users interact with crafted messages. Specifically, when replying to, forwarding, or editing an email, parts of another message within the same folder could be unintentionally embedded into the new message. This happens without any warning, resulting in potentially sensitive information being sent to unintended recipients. Mozilla has addressed this vulnerability in updates, specifically releasing fixes in Thunderbird versions 159 and 153.6 to protect user privacy.

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