CVE-2026-116272— MIME::Field::ParamVal versions before 5.521 for Perl do not flag a duplicate boundary parameter whose name contains a nested comment

Quick assessment

Affected

CVE-2026-116272

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Perl 的 MIME::Field::ParamVal 模块在 5.521 版本之前，无法识别名称中包含嵌套注释的重复边界（boundary）参数。当参数以或的形式书写时，该参数会被以其字面名称（即包含注释的完整字符串）存储，而不是被解析为标准的参数。因此，后续出现的第二个参数不会被报告为重复项，导致 MIME::Parser 会依据该第二个边界值对邮件内容进行拆分。遵循 RFC 5322 标准、在解析时跳过注释的邮件阅读器，会采用第一个边界值。这使得远程发送者能够利用此漏洞，将附件隐藏起来，从而绕过

AI Predicted 6.5 Difficulty: Easy EPSS 0.18% · P7 Updated Oct 29, 2026

Possible ATT&CK Techniques 2 AI

T1566 · Phishing T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

Vendor	Product	Version Range	Status
None	None	`< 5.521`	affected

Vulnerability Information

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Vulnerability Title

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

Source: CVE Program / CVE List V5

Vulnerability 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.

Source: CVE Program / CVE List V5

CVSS Information

N/A

Source: CVE Program / CVE List V5

Vulnerability Type

解释冲突

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
-	-	0 ~ 5.521	-

II. Public POCs for CVE-2026-116272

#	POC Description	Source Link	Shenlong Link

AI-Generated POC Premium

No public POC found.

III. Intelligence Information for CVE-2026-116272

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Other References for CVE-2026-116272 (1)

https://metacpan.org/release/DSKOLL/MIME-tools-5.521/changes release-notes

https://www.cve.org/CVERecord?id=CVE-2026-116272

IV. Related Vulnerabilities

Same weakness: CWE-436