CVE-2021-39132Network attack vector

Authenticated code execution via unrestricted YAML constructors

Published Aug 30, 2021 · Updated Aug 4, 2024

Deserialization in PagerDuty Rundeck before 3.3.14 and 3.4.0 through 3.4.2 allows remote authenticated users to execute server code. ScriptPluginProviderLoader.loadMetadataYaml uses SnakeYAML's unrestricted default constructor on plugin.yaml, permitting attacker-selected Java type tags instead of limiting objects to PluginMeta. Plugin uploads require system admin access; ACL uploads require create, update, or admin ACL rights, while the Enterprise-only POST path requires authentication without specific authorization.

CVSS severity8.8
High
EPSS probability1.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in PagerDuty Rundeck before 3.3.14 and 3.4.0 through 3.4.2 allows remote authenticated users to execute server code. ScriptPluginProviderLoader.loadMetadataYaml uses SnakeYAML's unrestricted default constructor on plugin.yaml, permitting attacker-selected Java type tags instead of limiting objects to PluginMeta. Plugin uploads require system admin access; ACL uploads require create, update, or admin ACL rights, while the Enterprise-only POST path requires authentication without specific authorization.

The record

CVE
CVE-2021-39132
Published
Aug 30, 2021
Updated
Aug 4, 2024
Vendor
PagerDuty
Product
Rundeck
Classifications
CWE-502, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 30, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.3.14
  2. Affected versionversion=>= 3.4.0, < 3.4.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

PagerDuty · Rundeckversion=< 3.3.14; version=>= 3.4.0, < 3.4.3

Published CVSS scores

8.8NISTCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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