Vulnerability Description
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.
Related Weaknesses (CWE)
References
FAQ
What is CVE-2026-116265?
CVE-2026-116265 is a documented vulnerability. 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= parame...
How severe is CVE-2026-116265?
CVSS scoring is not yet available for CVE-2026-116265. Check NVD for updates.
Is there a patch for CVE-2026-116265?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.