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.

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Fixes

Solution

Upgrade to MIME-tools 5.521 or later.


Workaround

No workaround given by the vendor.

History

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

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cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-10-28T17:34:06.757Z

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

Link: CVE-2026-116271

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

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

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

Link: CVE-2026-116271

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-28T18:45:07Z

Weaknesses