CVE-2026-116269 Affecting libmime-tools-perl package, versions *

Note: Versions mentioned in the description apply only to the upstream libmime-tools-perl package and not the libmime-tools-perl package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

MIME::Field::ParamVal versions before 5.521 for Perl turn an RFC 2231 filename with a hyphenated language tag into an empty recommended filename.

A parameter such as filename*=utf-8'en-US'payload.exe is converted to an encoded word with the language tag appended to the charset. The decoder strips the language suffix only when it is a single word, so it cannot resolve the charset UTF-8*EN-US and returns an empty string. The recommended_filename() method returns that empty string rather than falling back to the name parameter.

Other mail readers return payload.exe. A remote sender can get an attachment past a policy that checks file extensions on the recommended filename.

• https://advisory.echohq.com/cve/CVE-2026-116269
• https://metacpan.org/release/DSKOLL/MIME-tools-5.521/changes