CVE-2020-15646: Mozilla Thunderbird

Medium severity, CVSS 5.9. EPSS: 1% chance of exploitation in the next 30 days.

If an attacker intercepts Thunderbird's initial attempt to perform automatic account setup using the Microsoft Exchange autodiscovery mechanism, and the attacker sends a crafted response, then Thunderbird sends username and password over https to a server controlled by the attacker. This vulnerability affects Thunderbird < 68.10.0.

Affected products

• Mozilla Thunderbird: before 68.10.0 (fixed in 68.10.0)

Published 2020-10-08. Last modified 2026-06-17.