YAML versions before 1.30 for Perl allow a loaded document to trigger the DESTROY method of arbitrary classes.

A perl/hash:Class tag blesses a hash into the class it names. The document supplies the object's fields, and Perl calls DESTROY when it goes out of scope.

What DESTROY does depends on the classes the process has loaded. With File::Temp::Dir from core Perl, it can delete a directory tree the document names.
Advisories

No advisories yet.

Fixes

Solution

Upgrade to YAML 1.30 or later.


Workaround

For deployments that cannot upgrade to YAML 1.30, set $YAML::LoadBlessed = 0 before loading untrusted input. The option exists from YAML 1.25.

History

Mon, 05 Oct 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H'}

threat_severity

Important


Mon, 05 Oct 2026 07:00:00 +0000

Type Values Removed Values Added
Description YAML versions before 1.30 for Perl allow a loaded document to trigger the DESTROY method of arbitrary classes. A perl/hash:Class tag blesses a hash into the class it names. The document supplies the object's fields, and Perl calls DESTROY when it goes out of scope. What DESTROY does depends on the classes the process has loaded. With File::Temp::Dir from core Perl, it can delete a directory tree the document names.
Title YAML versions before 1.30 for Perl allow a loaded document to trigger the DESTROY method of arbitrary classes
Weaknesses CWE-470
CWE-502
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-10-05T06:49:17.583Z

Reserved: 2026-09-21T21:18:28.499Z

Link: CVE-2017-20285

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-05T07:16:29.017

Modified: 2026-10-05T07:16:29.017

Link: CVE-2017-20285

cve-icon Redhat

Severity : Important

Publid Date: 2026-10-05T06:49:17Z

Links: CVE-2017-20285 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-05T08:30:04Z

Weaknesses