CVE-2019-11755: Mozilla Thunderbird

High severity, CVSS 7.5. EPSS: 1.1% chance of exploitation in the next 30 days.

A crafted S/MIME message consisting of an inner encryption layer and an outer SignedData layer was shown as having a valid digital signature, although the signer might have had no access to the contents of the encrypted message, and might have stripped a different signature from the encrypted message. Previous versions had only suppressed showing a digital signature for messages with an outer multipart/signed layer. This vulnerability affects Thunderbird < 68.1.1.

Affected products

• Mozilla Thunderbird: before 68.1.1 (fixed in 68.1.1)

Published 2019-09-27. Last modified 2026-06-17.