CVE-2026-116265

The record

MIME::Field::ParamVal versions before 5.521 for Perl do not flag an ambiguous multipart boundary written as RFC 2231 continuations. The boundary ambiguity checks look only at a plain boundary= parameter, and a boundary split into RFC 2231 sections (boundary*0=, boundary*1= and so on) is joined after they have run. A repeated section number is concatenated rather than reported as a duplicate. From version 5.518, an encoded word or trailing whitespace in such a boundary also goes unflagged, although multipart_boundary() decodes or strips it. A remote sender can make MIME::Parser split a message on a different boundary than other mail readers, hiding an attachment from a filter that relies on ambiguous_content() while the recipient's mail client shows it.

Affected packages

Related vulnerabilities

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• CVE-2026-119200 Nuxt is an open-source web development framework for Vue.js. CWE-436
• CVE-2026-119190 Forge (also called node-forge) is a native implementation of Transport Layer Security in… CWE-436
• CVE-2026-116266 MIME::Head versions from 5.518 before 5.521 for Perl decode a partly encoded multipart… CWE-436
• CVE-2026-116272 MIME::Field::ParamVal versions before 5.521 for Perl do not flag a duplicate boundary… CWE-436
• CVE-2026-116269 MIME::Field::ParamVal versions before 5.521 for Perl turn an RFC 2231 filename with a… CWE-436
• CVE-2026-116264 MIME::Field::ParamVal versions before 5.521 for Perl allow one invalid Content-Type… CWE-436
• CVE-2026-116695 Crass is a Ruby CSS parser that is compliant with the CSS Syntax Level 3 specification. CWE-436