MIME::Field::ParamVal versions before 5.521 for Perl do not flag an ambiguous multipart boundary...
Affected packages
| Ecosystem | Package | Affected | Fixed |
|---|---|---|---|
| https://cpan.org/modules | MIME-tools |
< 5.521 |
5.521 |
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-116265 libmime-tools-perl
- Ubuntu UBUNTU-CVE-2026-116265 libmime-tools-perl
Original description The description as published by the source.
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 (boundary0=, boundary1= 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.
Source: CVE.org (CVE Program・cvelistV5) NVD GitHub Advisory
References
- web metacpan.org
- web nvd.nist.gov
- web github.com