MIME::Field::ParamVal up to 5.520 Decoder recommended_filename improper authentication

Summaryinfo

A vulnerability has been found in MIME::Field::ParamVal up to 5.520 and classified as problematic. This vulnerability affects the function recommended_filename of the component Decoder. The manipulation leads to improper authentication. This vulnerability is listed as CVE-2026-116269. The attack may be initiated remotely. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in MIME::Field::ParamVal up to 5.520. This issue affects the function recommended_filename of the component Decoder. The manipulation with an unknown input leads to a improper authentication vulnerability. Using CWE to declare the problem leads to CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Impacted is integrity. The summary by CVE is:

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.

It is possible to read the advisory at metacpan.org. The identification of this vulnerability is CVE-2026-116269 since 10/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 5.521 eliminates this vulnerability.

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Productinfo

Name

• MIME::Field::ParamVal

Version

• 5.520

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

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