{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-116266","assignerOrgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","state":"PUBLISHED","assignerShortName":"CPANSec","dateReserved":"2026-10-25T18:05:02.235Z","datePublished":"2026-10-28T17:32:28.565Z","dateUpdated":"2026-10-28T17:32:28.565Z"},"containers":{"cna":{"affected":[{"collectionURL":"https://cpan.org/modules","defaultStatus":"unaffected","modules":["MIME::Head"],"packageName":"MIME-tools","packageURL":"pkg:cpan/MIME-tools","programFiles":["lib/MIME/Head.pm","lib/MIME/Field/ParamVal.pm"],"programRoutines":[{"name":"MIME::Head::multipart_boundary"},{"name":"MIME::Field::ParamVal::parse_params"}],"repo":"https://salsa.debian.org/dskoll/mime-tools","versions":[{"lessThan":"5.521","status":"affected","version":"5.518","versionType":"custom"}]}],"descriptions":[{"lang":"en","value":"MIME::Head versions from 5.518 before 5.521 for Perl decode a partly encoded multipart boundary without flagging the parse as ambiguous.\n\nThe multipart_boundary() method decodes RFC 2047 encoded words anywhere in the boundary, but the ambiguity check only fires when the whole value is one encoded word. A boundary such as abc=?us-ascii?Q?def?= is used as abcdef, and ambiguous_content() returns false.\n\nEncoded words are not allowed in parameters, so other mail readers split the message on the literal value. A remote sender can hide an attachment from a filter that relies on ambiguous_content() while the recipient's mail client shows it."}],"problemTypes":[{"descriptions":[{"cweId":"CWE-436","description":"CWE-436 Interpretation Conflict","lang":"en","type":"CWE"}]}],"providerMetadata":{"orgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","shortName":"CPANSec","dateUpdated":"2026-10-28T17:32:28.565Z"},"references":[{"tags":["release-notes"],"url":"https://metacpan.org/release/DSKOLL/MIME-tools-5.521/changes"}],"solutions":[{"lang":"en","value":"Upgrade to MIME-tools 5.521 or later."}],"source":{"discovery":"UNKNOWN"},"title":"MIME::Head versions from 5.518 before 5.521 for Perl decode a partly encoded multipart boundary without flagging the parse as ambiguous","x_generator":{"engine":"cpansec-cna-tool 0.1"}}}}