Description
MIME::Field::ParamVal versions before 5.521 for Perl do not flag a duplicate boundary parameter whose name contains a nested comment.

A parameter written boundary((c))="A" or boundary(\))="A" is stored under that literal name rather than as boundary. A second boundary parameter is then not reported as a duplicate, and MIME::Parser splits the message on it.

Readers that skip comments as RFC 5322 allows take the first boundary instead. A remote sender can hide an attachment from a filter that relies on ambiguous_content() while the recipient's mail client shows it.
Published: 2026-10-28
Score: 5.3 Medium
EPSS: < 1% Very Low
KEV: No
AI Analysis

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Remediation

Vendor Solution

Upgrade to MIME-tools 5.521 or later.

Tracking

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Advisories

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History

Fri, 30 Oct 2026 12:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-115
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}

threat_severity

Moderate


Wed, 28 Oct 2026 22:30:00 +0000

Type Values Removed Values Added
First Time appeared Perl
Perl mime::field::paramval
Vendors & Products Perl
Perl mime::field::paramval

Wed, 28 Oct 2026 17:45:00 +0000

Type Values Removed Values Added
Description MIME::Field::ParamVal versions before 5.521 for Perl do not flag a duplicate boundary parameter whose name contains a nested comment. A parameter written boundary((c))="A" or boundary(\))="A" is stored under that literal name rather than as boundary. A second boundary parameter is then not reported as a duplicate, and MIME::Parser splits the message on it. Readers that skip comments as RFC 5322 allows take the first boundary instead. A remote sender can hide an attachment from a filter that relies on ambiguous_content() while the recipient's mail client shows it.
Title MIME::Field::ParamVal versions before 5.521 for Perl do not flag a duplicate boundary parameter whose name contains a nested comment
Weaknesses CWE-436
References

Subscriptions

Perl Mime::field::paramval
cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-10-28T17:34:25.862Z

Reserved: 2026-10-25T18:05:02.236Z

Link: CVE-2026-116272

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-28T18:17:13.690

Modified: 2026-10-29T15:11:53.000

Link: CVE-2026-116272

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-28T17:34:25Z

Links: CVE-2026-116272 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-30T13:45:15Z

Weaknesses