CVE-2021-21678Network attack vector

CSRF action execution via substring-based crumb exclusion

Published Aug 31, 2021 · Updated Aug 3, 2024

CSRF bypass in Jenkins SAML Plugin 1.1.3 through 2.0.7 allows remote attackers to invoke protected Jenkins actions via crafted URLs. SamlCrumbExclusion.process searches for /securityRealm/finishLogin anywhere after the first path character instead of requiring it at the path start. A victim with sufficient Jenkins permissions must follow the crafted URL, after which the requested action executes without a valid crumb.

CVSS severity8.8
High
EPSS probability0.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CSRF bypass in Jenkins SAML Plugin 1.1.3 through 2.0.7 allows remote attackers to invoke protected Jenkins actions via crafted URLs. SamlCrumbExclusion.process searches for /securityRealm/finishLogin anywhere after the first path character instead of requiring it at the path start. A victim with sufficient Jenkins permissions must follow the crafted URL, after which the requested action executes without a valid crumb.

The record

CVE
CVE-2021-21678
Published
Aug 31, 2021
Updated
Aug 3, 2024
Vendor
Jenkins Project
Product
Jenkins SAML Plugin
Classifications
CWE-352, CWE-693, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 31, 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=1.1.3 <unspecified
  2. Affected versionversion=unspecified <=2.0.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Jenkins Project · Jenkins SAML Pluginversion=1.1.3 <unspecified; version=unspecified <=2.0.7

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)
CWE-693Protection Mechanism Failure
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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