9.1

CVSS Score

3.1

-

CVSS Score

Basic Information

CVE ID

CVE-2021-21688

GHSA ID

GHSA-m9hr-259f-2v23

EPSS Score

0.56895%

CWE

CWE-862

Published

5/24/2022

Updated

12/18/2023

KEV Status

Technology

Java

Basic Information

CVE ID

GHSA ID

EPSS Score

CWE

Published

Updated

KEV Status

Technology

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CVE-2021-21688

CVE-2021-21688: Multiple vulnerabilities allow bypassing path filtering of agent-to-controller access control in Jenkins

The agent-to-controller security subsystem limits which files on the Jenkins controller can be accessed by agent processes.

Multiple vulnerabilities in the file path filtering implementation of Jenkins 2.318 and earlier, LTS 2.303.2 and earlier allow agent processes to read and write arbitrary files on the Jenkins controller file system, and obtain some information about Jenkins controller file systems.

SECURITY-2484 / CVE-2021-21688: FilePath#reading(FileVisitor) does not reject any operations, allowing users to have unrestricted read access using certain operations (creating archives, #copyRecursiveTo).

We expect that most of these vulnerabilities have been present since SECURITY-144 was addressed in the 2014-10-30 security advisory.

Jenkins 2.319, LTS 2.303.3 addresses these security vulnerabilities.

SECURITY-2484 / CVE-2021-21688: FilePath#reading(FileVisitor) correctly rejects operations if they operate on files outside allowed directories.

As some common operations are now newly subject to access control, it is expected that plugins sending commands from agents to the controller may start failing. Additionally, the newly introduced path canonicalization means that instances using a custom builds directory (Java system property jenkins.model.Jenkins.buildsDir) or partitioning JENKINS_HOME using symbolic links may fail access control checks. See the documentation for how to customize the configuration in case of problems.

If you are unable to immediately upgrade to Jenkins 2.319, LTS 2.303.3, you can install the Remoting Security Workaround Plugin. It will prevent all agent-to-controller file access using FilePath APIs. Because it is more restrictive than Jenkins 2.319, LTS 2.303.3, more plugins are incompatible with it. Make sure to read the plugin documentation before installing it.

(GitHub Advisory)

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CVE-2021-21688

CVE-2021-21688:

9.1

CVSS Score

3.1

-

CVSS Score

Basic Information

CVE ID

CVE-2021-21688

GHSA ID

GHSA-m9hr-259f-2v23

EPSS Score

0.56895%

CWE

CWE-862

Published

5/24/2022

Updated

12/18/2023

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:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
org.jenkins-ci.main:jenkins-core	maven	>= 2.304, <= 2.318	2.319
org.jenkins-ci.main:jenkins-core	maven	<= 2.303.2	2.303.3

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability description explicitly identifies FilePath#reading(FileVisitor) as the root cause (CVE-2021-21688/SECURITY-2484). The commit diff shows removal of security-related serialization checks in FilePath's inner classes, and the advisory states this method failed to reject operations outside allowed directories. The test case additions in Security2455Test.java validate() that archive operations (like unzip) were improperly allowed, which aligns with the described vulnerability pattern. The function is directly named in both the CVE description and security advisory as the flawed component.

Vulnerable functions

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WAF Protection Rules

WAF Rule

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Reasoning

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9.1

-

Basic Information

Basic Information

Concerned about an active attack path?

CVE-2021-21688: Multiple vulnerabilities allow bypassing path filtering of agent-to-controller access control in Jenkins

CVE-2021-21688:

9.1

-

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

Technical Details

9.1

9.1

Basic Information

Basic Information

Vulnerability IntelligenceMiggo AI

Root Cause Analysis

Vulnerable functions

WAF Protection Rules

WAF Rule

Reasoning

CVE-2021-21688: Multiple vulnerabilities allow bypassing path filtering of agent-to-controller access control in Jenkins

Vulnerability Intelligence
Miggo AI

Vulnerability Intelligence
Miggo AI

Vulnerability Intelligence
Miggo AI