CVE-2021-21679Network attack vector

CSRF protection bypass via permissive GraphProxy suffix match

Published Aug 31, 2021 · Updated Aug 3, 2024

CSRF in Jenkins Microsoft Entra ID Plugin 164.v5b48baa961d2 through 179.vf6841393099e allows remote attackers to bypass CSRF protection. AzureSecurityRealm.CrumbExempt exempts any path ending in GraphProxy/v1.0/$batch from crumb validation instead of requiring the JavaScript client to send a crumb. Exploitation requires a Jenkins user to open a crafted URL, after which requests can reach target URLs with that user's permissions.

CVSS severity8.8
High
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

CSRF in Jenkins Microsoft Entra ID Plugin 164.v5b48baa961d2 through 179.vf6841393099e allows remote attackers to bypass CSRF protection. AzureSecurityRealm.CrumbExempt exempts any path ending in GraphProxy/v1.0/$batch from crumb validation instead of requiring the JavaScript client to send a crumb. Exploitation requires a Jenkins user to open a crafted URL, after which requests can reach target URLs with that user's permissions.

The record

CVE
CVE-2021-21679
Published
Aug 31, 2021
Updated
Aug 3, 2024
Vendor
Jenkins Project
Product
Microsoft Entra ID (previously Azure AD) Plugin
Classifications
CWE-693, CWE-352, T1204.001
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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=164.v5b48baa961d2 <unspecified
  2. Affected versionversion=unspecified <=179.vf6841393099e

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Jenkins Project · Microsoft Entra ID (previously Azure AD) Pluginversion=164.v5b48baa961d2 <unspecified; version=unspecified <=179.vf6841393099e

Published CVSS scores

8.8GitHub Advisory DatabaseCVSS: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-693Protection Mechanism Failure
CWE-352Cross-Site Request Forgery (CSRF)
T1204.001Malicious Link

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo