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CVE.org (no NVD analysis yet)· CNA CPANSec

CVE-2017-20285: YAML versions before 1.30 for Perl allow a loaded document to trigger the DESTROY method of arbitrary classes

CriticalCVSS 9.1 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 36/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.34% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: perl-YAML (AlmaLinux:8) 1.24-4.module_el8.10.0+4341+ab0ec422; libyaml-perl (Debian:12) 1.30-1; perl-YAML (openSUSE:Tumbleweed) 1.321.0-2.1.

Low priority for now. Upgrade to perl-YAML (AlmaLinux:8) 1.24-4.module_el8.10.0+4341+ab0ec422; libyaml-perl (Debian:12) 1.30-1; perl-YAML (openSUSE:Tumbleweed) 1.321.0-2.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Oct 5, 2026
Updated
Oct 6, 2026
EPSS
0.3% · 27th percentile

Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
36 / 40 · 9.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2017-20285

When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (CPANSec). Independent of NVD's CPE analysis and usually ahead of it.

  • cpan.org/modules YAML

    • before 1.30affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8perl-YAMLbefore 1.24-4.module_el8.10.0+4341+ab0ec4221.24-4.module_el8.10.0+4341+ab0ec422
Debian:12libyaml-perlbefore 1.30-11.30-1
openSUSE:Tumbleweedperl-YAMLbefore 1.321.0-2.11.321.0-2.1
Rocky Linux:8perl-YAMLbefore 0:1.24-4.module+el8.10.0+40403+9457ea6c0:1.24-4.module+el8.10.0+40403+9457ea6c
Rocky Linux:8perl-YAMLbefore 0:1.24-4.module+el8.10.0+40403+945581600:1.24-4.module+el8.10.0+40403+94558160
Rocky Linux:8perl-YAMLbefore 0:1.24-4.module+el8.10.0+40403+bd06a93a0:1.24-4.module+el8.10.0+40403+bd06a93a
Rocky Linux:8perl-YAMLbefore 0:1.24-4.module+el8.10.0+40403+df14587c0:1.24-4.module+el8.10.0+40403+df14587c

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:perl-YAML1.24-4.module_el8.10.0+4341+ab0ec422 · AlmaLinux:8Package registry (OSV)
debian:libyaml-perl1.30-1 · Debian:12Package registry (OSV)
opensuse:perl-YAML1.321.0-2.1 · openSUSE:TumbleweedPackage registry (OSV)
rocky linux:perl-YAML0:1.24-4.module+el8.10.0+40403+bd06a93a · Rocky Linux:8Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recorded+1 d
  3. TodayNov 13, 2026+39 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Not on record for this CVE: researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-470 · Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → none
  2. CVSS— → 9.1
  3. Severity— → critical
  4. Fix✗ → ✓
  5. Exploit maturity— → none

For records you follow, these changes also arrive as notifications. →

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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