CVE-2017-20285: Insecure Deserialization (CVSS 9.1)

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.

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CVSS v3.1 Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0018

Probability of exploitation

0.07%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-470 CWE-470

CWE-502 Deserialization of Untrusted Data

References

Other References

https://github.com/ingydotnet/yaml-pm/commit/471314bbdcbd62077eea32755929122aa8bd00a3.patch https://github.com/ingydotnet/yaml-pm/commit/7736f38bd02e4f9f77d5468721e3be3d7b34a8ec.patch https://github.com/ingydotnet/yaml-pm/issues/176 https://metacpan.org/release/TINITA/YAML-1.30/changes http://www.openwall.com/lists/oss-security/2026/10/05/8

Frequently Asked Questions

What is CVE-2017-20285? +

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. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2017-20285? +

CVE-2017-20285 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0018, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2017-20285? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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