CVE-2019-11755 Security feature bypass in Thunderbird

What is CVE-2019-11755?

CVE-2019-11755 is a high-severity vulnerability in Mozilla Thunderbird, published on 27 Sep 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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.

Weakness: CWE-347

Which versions are affected by CVE-2019-11755?

It affects 1 product.

Products include Mozilla Thunderbird.

How do I fix CVE-2019-11755?

Upgrade to a fixed version.

Is CVE-2019-11755 being exploited?

There is no known exploitation of CVE-2019-11755 in the wild and no public exploit code.

Other vulnerabilities in Mozilla Thunderbird

• CVE-2026-92238 Ambiguous parsing of mail headers Critical 9.8
• CVE-2026-84637 Calendar invitation attachments could launch local executables Critical 9.8
• CVE-2021-43529 Memory corruption in Thunderbird Critical 9.8
• CVE-2019-11703 Memory corruption in Thunderbird Critical 9.8
• CVE-2019-11704 Memory corruption in Thunderbird Critical 9.8

All Mozilla Thunderbird vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2019-11755, GHSA-42rq-cwg9-m583, MGASA-2019-0292, UBUNTU-CVE-2019-11755.