8

CVSS Score

3.1

-

CVSS Score

Basic Information

CVE ID

CVE-2021-21604

GHSA ID

GHSA-qv6f-rcv6-6q3x

EPSS Score

0.78469%

CWE

CWE-502

Published

5/24/2022

Updated

12/14/2023

KEV Status

Technology

Java

Basic Information

CVE ID

GHSA ID

EPSS Score

CWE

Published

Updated

KEV Status

Technology

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CVE-2021-21604

CVE-2021-21604: Improper handling of REST API XML deserialization errors in Jenkins

Jenkins provides XML REST APIs to configure views, jobs, and other items. When deserialization fails because of invalid data, Jenkins 2.274 and earlier, LTS 2.263.1 and earlier stores invalid object references created through these endpoints in the Old Data Monitor. If an administrator discards the old data, some erroneous data submitted to these endpoints may be persisted.

This allows attackers with View/Create, Job/Create, Agent/Create, or their respective */Configure permissions to inject crafted content into Old Data Monitor that results in the instantiation of potentially unsafe objects when discarded by an administrator.\n\nJenkins 2.275, LTS 2.263.2 does not record submissions from users in Old Data Monitor anymore.

In case of problems, the Java system properties hudson.util.RobustReflectionConverter.recordFailuresForAdmins and hudson.util.RobustReflectionConverter.recordFailuresForAllAuthentications can be set to true to record configuration data submissions from administrators or all users, partially or completely disabling this fix.

(GitHub Advisory)

Miggo Vulnerability Database

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CVE-2021-21604

CVE-2021-21604:

8

CVSS Score

3.1

-

CVSS Score

Basic Information

CVE ID

CVE-2021-21604

GHSA ID

GHSA-qv6f-rcv6-6q3x

EPSS Score

0.78469%

CWE

CWE-502

Published

5/24/2022

Updated

12/14/2023

KEV Status

Technology

Java

Basic Information

CVE ID

GHSA ID

EPSS Score

CWE

Published

Updated

KEV Status

Technology

Technical Details

CVSS Vector

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

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
org.jenkins-ci.main:jenkins-core	maven	<= 2.263.1	2.263.2
org.jenkins-ci.main:jenkins-core	maven	>= 2.264, <= 2.274	2.275

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability occurs in XML deserialization error handling where invalid data was stored in Old Data Monitor. The commit diff shows the fix added a security check (shouldReportUnloadableDataForCurrentUser()) in doUnmarshal to restrict error recording based on user permissions. The original code lacked this check, allowing unauthorized users to poison the Old Data Monitor. The function's direct involvement in deserialization error handling and the security-focused patch confirm its role in the vulnerability.

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

WAF Protection Rules

WAF Rule

W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.W** rul*s *v*il**l* *or Mi**o *ustom*rs only.

Reasoning

*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.*v*il**l* *or Mi**o *ustom*rs only.

8

-

Basic Information

Basic Information

Concerned about an active attack path?

CVE-2021-21604: Improper handling of REST API XML deserialization errors in Jenkins

CVE-2021-21604:

8

-

Basic Information

Basic Information

Technical Details

Technical Details

Vulnerability IntelligenceMiggo AI

Root Cause Analysis

Vulnerable functions

WAF Protection Rules

WAF Rule

Reasoning

Vulnerability IntelligenceMiggo AI

CVE-2021-21604: Improper handling of REST API XML deserialization errors in Jenkins

8

8

Technical Details

Vulnerability IntelligenceMiggo AI

Root Cause Analysis

Vulnerable functions

WAF Protection Rules

WAF Rule

Reasoning

Basic Information

Basic Information

Vulnerability Intelligence
Miggo AI

Vulnerability Intelligence
Miggo AI

Vulnerability Intelligence
Miggo AI