CVE-2021-21659Network attack vector

Secret extraction and SSRF via external entities

Published May 25, 2021 · Updated Aug 3, 2024

XXE in Jenkins Project URLTrigger Plugin 0.48 and earlier allows remote authenticated users to extract controller or agent secrets. The plugin's XML response-content parser resolves external entities in attacker-controlled documents instead of disabling entity resolution. Exploitation requires Job/Configure permission or control of a polled XML resource and can also issue server-side requests or interrupt service.

CVSS severity8.1
High
EPSS probability66.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XXE in Jenkins Project URLTrigger Plugin 0.48 and earlier allows remote authenticated users to extract controller or agent secrets. The plugin's XML response-content parser resolves external entities in attacker-controlled documents instead of disabling entity resolution. Exploitation requires Job/Configure permission or control of a polled XML resource and can also issue server-side requests or interrupt service.

The record

CVE
CVE-2021-21659
Published
May 25, 2021
Updated
Aug 3, 2024
Vendor
Jenkins Project
Product
URLTrigger Plugin
Classifications
CWE-611, T1005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 25, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=unspecified <=0.48

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Jenkins Project · URLTrigger Pluginversion=unspecified <=0.48

Published CVSS scores

8.1GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/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.

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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-611Improper Restriction of XML External Entity Reference
T1005Data from Local System

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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