Description
MIME::Parser::FileUnder versions before 5.521 for Perl reuse a pre-created output directory and follow symlinks in it, letting local users redirect attachment writes.

Each message is written to a directory named msg-<time>-<pid>-<n> under the output base, and an existing directory of that name is used as is. A file name counts as unused when nothing exists at that path, which holds for a dangling symlink, and the body file is then opened in a way that follows the link.

When the output base is writable by other users, as with output_under("/tmp"), a local user can pre-create the directory with a symlink named like an attachment. The parser then writes the attachment to the link target with the privileges of the parsing process.
Published: 2026-10-28
Score: 7 High
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, 06 Nov 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Thu, 05 Nov 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 6.3, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H'}

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}


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

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 6.3, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H'}

threat_severity

Moderate


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

Type Values Removed Values Added
First Time appeared Perl
Perl mime::parser::fileunder
Vendors & Products Perl
Perl mime::parser::fileunder

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

Type Values Removed Values Added
Description MIME::Parser::FileUnder versions before 5.521 for Perl reuse a pre-created output directory and follow symlinks in it, letting local users redirect attachment writes. Each message is written to a directory named msg-<time>-<pid>-<n> under the output base, and an existing directory of that name is used as is. A file name counts as unused when nothing exists at that path, which holds for a dangling symlink, and the body file is then opened in a way that follows the link. When the output base is writable by other users, as with output_under("/tmp"), a local user can pre-create the directory with a symlink named like an attachment. The parser then writes the attachment to the link target with the privileges of the parsing process.
Title MIME::Parser::FileUnder versions before 5.521 for Perl reuse a pre-created output directory and follow symlinks in it, letting local users redirect attachment writes
Weaknesses CWE-59
References

Subscriptions

Perl Mime::parser::fileunder
cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-11-05T20:38:49.025Z

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

Link: CVE-2026-116271

cve-icon Vulnrichment

Updated: 2026-11-05T20:35:37.923Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-28T18:17:13.580

Modified: 2026-11-05T21:18:38.830

Link: CVE-2026-116271

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-28T17:34:06Z

Links: CVE-2026-116271 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-11-05T22:30:17Z

Weaknesses