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Security Advisories

CloudBees Security Advisory2026-08-05

This advisory announces vulnerabilities in 

,

and

Jenkins

,

and

CloudBees CI

Agent-to-controller deserialization filter bypass

SECURITY-3911 / CVE-2026-70426‍

‍Severity (CVSS): Critical‍

‍Description:

Jenkins uses the Remoting library (typically agent.jar or remoting.jar) for communication between the controller and agents via serialized Java objects. In CloudBees CI, Remoting is also used for most communication between Operations Center and controllers. To protect against deserialization vulnerabilities, Jenkins enforces the JEP-200 class filter during deserialization of objects received over a Remoting channel on the controller.

In Remoting 3384.v60d89463d9e0 and earlier, except 3355.3357.v931d3c992987, included in CloudBees CI 2.568.1.37445 and earlier, Jenkins 2.575 and earlier, LTS 2.568.1 and earlier, the JEP-200 class filter is not applied to classes resolved via a fallback path in the Remoting deserialization implementation. This allows agent processes, code running on agents, and attackers with Agent/Connect permission to bypass the JEP-200 deserialization filter for classes on the Jenkins core classpath, which could be leveraged to execute code on the Jenkins controller. In CloudBees CI, administrators of connected controllers may be able to bypass the JEP-200 deserialization filter to execute code on Operations Center.

[!NOTE]

This is limited to classes on the Jenkins core classpath (i.e., bundled with Jenkins or part of the Java platform) that are not on the pre-JEP-200 deserialization denylist. Dependencies bundled with plugins will not be deserialized.

[/]

The Remoting library in CloudBees CI 2.568.2.37664, Jenkins 2.576, LTS 2.568.2 also applies the class filter on the fallback code path.

[!NOTE]

A workaround for this vulnerability is available in case updating to a fixed version is not possible. See this article for details.

[/]

Link following vulnerability allows arbitrary file creation

SECURITY-3930 / CVE-2026-70427

‍‍Severity (CVSS): High‍

‍Description:

CloudBees CI 2.568.1.37445 and earlier, Jenkins 2.575 and earlier, LTS 2.568.1 and earlier does not safely handle symbolic links with effectively empty names during the extraction of .tar and .tar.gz archives. This allows attackers able to control agent processes to provide crafted archives to the controller to write files to arbitrary locations on the file system, restricted only by file system access permissions of the user running Jenkins. This can result in code execution by, e.g., writing malicious scripts to the JENKINS_HOME/init.groovy.d/ directory (feature documentation), or deploying plugins to JENKINS_HOME/plugins/.

[!NOTE]

This is due to an incomplete fix of SECURITY-3657.

[/]

CloudBees CI 2.568.2.37664, Jenkins 2.576, LTS 2.568.2 refuses to extract files from .tar and .tar.gz archives that contain symbolic links with effectively empty names.

[!NOTE]

A workaround for this vulnerability is available in case updating to a fixed version is not possible. See this article for details.

[/]

Path traversal vulnerability in file parameters

SECURITY-3927 / CVE-2026-70428‍

‍Severity (CVSS): High‍

‍Description:

CloudBees CI 2.568.1.37445 and earlier, Jenkins 2.575 and earlier, LTS 2.568.1 and earlier improperly identifies file paths attempting path traversal in file parameter names. This allows attackers with Item/Configure and Item/Build permission to write files to arbitrary locations on the controller file system, restricted only by file system access permissions of the user running Jenkins. This can result in code execution by, e.g., writing malicious scripts to the JENKINS_HOME/init.groovy.d/ directory (feature documentation), or deploying plugins to JENKINS_HOME/plugins/.

CloudBees CI 2.568.2.37664, Jenkins 2.576, LTS 2.568.2 improves the identification of file paths attempting path traversal in file parameter names, preventing writing files to arbitrary locations on the file system.

Improper handling of case sensitivity allows privilege escalation

SECURITY-3924 / CVE-2026-70429

‍‍Severity (CVSS): High

‍‍Description:

CloudBees CI 2.568.1.37445 and earlier, Jenkins 2.575 and earlier, LTS 2.568.1 and earlier handles case-insensitivity in user names and group names inconsistently. While the canonical ID for a case-insensitive user or group name is created by lowercasing the name, comparisons of user names and group names are done using String#equalsIgnoreCase. The latter considers some Unicode characters to be equal to other characters, while the former does not (e.g., the letter "dotless i" ı being equal to regular lowercase i). This allows attackers able to create new users or groups with names that case-insensitively match other characters to impersonate other users or be granted their permissions.

[!WARNING]

This requires a security realm that allows these characters in user names or group names, and allows creation of users or groups that case-insensitively match existing users or groups. The Jenkins user database does not allow users to sign up with usernames outside of the ASCII range.

[/]

CloudBees CI 2.568.2.37664, Jenkins 2.576, LTS 2.568.2 compares usernames and group names using their canonical form and only considers them equal if their canonical forms are equal.

Users with Overall/Manage permission can instantiate any types related to configuration

SECURITY-3916 / CVE-2026-70430

‍‍Severity (CVSS): Low‍

‍Description:

CloudBees CI 2.568.1.37445 and earlier, Jenkins 2.575 and earlier, LTS 2.568.1 and earlier does not restrict the types of objects that can be instantiated as part of the project naming strategy configuration. This allows attackers with Overall/Manage permission to instantiate arbitrary types related to configuration, including those intended for configuration only by administrators.

CloudBees CI 2.568.2.37664, Jenkins 2.576, LTS 2.568.2 restricts the types of objects that can be instantiated as part of the project naming strategy configuration to those related to that feature.

Arbitrary code execution vulnerability in Multijob Plugin

SECURITY-3823 (1) / CVE-2026-70431‍

‍Severity (CVSS): High‍

‍Affected plugin: jenkins-multijob-plugin

‍‍Description:

Multijob Plugin 669.v9d96a_d9c71b_0 and earlier provides Groovy scripting features that do not integrate with Script Security Plugin.

This vulnerability allows attackers with Item/Create or Item/Configure permission to execute arbitrary code in the context of the Jenkins controller JVM.

Multijob Plugin 677.v7ffc23d6a_4c2 integrates with Script Security Plugin to enforce sandboxing of Groovy scripts.

CSRF vulnerability in Multijob Plugin allows arbitrary code execution

SECURITY-3823 (2) / CVE-2026-70432

‍‍Severity (CVSS): High

‍‍Affected plugin: jenkins-multijob-plugin

‍‍Description:

Multijob Plugin 669.v9d96a_d9c71b_0 and earlier does not require POST requests for a form validation endpoint, resulting in a cross-site request forgery (CSRF) vulnerability.

This vulnerability allows attackers to execute arbitrary code in the context of the Jenkins controller JVM.

Multijob Plugin 677.v7ffc23d6a_4c2 requires POST requests for the affected form validation endpoint.

Missing permission checks in HCL AppScan Plugin allow enumerating credentials IDs

SECURITY-3771 / CVE-2026-70433

‍‍Severity (CVSS): Medium

‍‍Affected plugin: appscan

‍‍Description:

HCL AppScan Plugin 1.8.3 and earlier does not perform permission checks in multiple HTTP endpoints.

This allows attackers with Overall/Read permission to enumerate credentials IDs of credentials stored in Jenkins. Those can be used as part of an attack to capture the credentials using another vulnerability.

HCL AppScan Plugin 1.8.4 requires appropriate permissions in the affected HTTP endpoints.

CSRF vulnerability and missing permission checks in SCM-Manager Plugin

SECURITY-3888 / CVE-2026-70434 (CSRF), CVE-2026-70435 (permission check)‍‍

Severity (CVSS): Medium‍‍

Affected plugin: scm-manager

‍‍Description:

SCM-Manager Plugin 1.11.1 and earlier does not perform permission checks in several HTTP endpoints.

This allows attackers with Overall/Read permission to connect to an attacker-specified HTTP URL using attacker-specified credentials IDs obtained through another method, capturing credentials stored in Jenkins.

Additionally, these endpoints do not require POST requests, resulting in a cross-site request forgery (CSRF) vulnerability.

SCM-Manager Plugin 1.12.1 requires POST requests and Item/Configure permission for these endpoints.

Missing permission check in External Workspace Manager Plugin allows reading workspace files

SECURITY-3907 / CVE-2026-70436‍

‍Severity (CVSS): Medium‍

‍Affected plugin: external-workspace-manager‍

‍Description:

External Workspace Manager Plugin 1.4.1 and earlier does not perform a permission check (1.4.0 and earlier) or performs an improper permission check (1.4.1) when providing access to externally-managed workspaces through the workspace browser.

This allows attackers with Overall/Read permission to read files in workspaces they are not authorized to access.

External Workspace Manager Plugin 1.4.2 performs the expected permission check before providing access to externally-managed workspaces through the workspace browser.

Non-constant time webhook bearer token comparison in Webhook Secret Credentials Provider Plugin

SECURITY-3918 / CVE-2026-70437‍

‍Severity (CVSS): Low‍‍

Affected plugin: webhook-secret-credentials-provider‍

‍Description:

Webhook Secret Credentials Provider Plugin 16.v0cfa_f0215cf5 and earlier does not use a constant-time comparison function when checking whether the provided and expected webhook bearer token are equal.

This could potentially allow attackers to use statistical methods to obtain a valid webhook bearer token.

Webhook Secret Credentials Provider Plugin 32.v09c9b_522f0a_8 uses a constant-time comparison when validating the webhook bearer token.

Missing permission checks in Parameterized Remote Trigger Plugin allow enumerating credentials IDs

SECURITY-3768 / CVE-2026-70438

‍‍Severity (CVSS): Medium‍

‍Affected plugin: Parameterized-Remote-Trigger‍

‍Description:

Parameterized Remote Trigger Plugin 3.2.2 and earlier does not perform permission checks in HTTP endpoints.

This allows attackers with Overall/Read permission to enumerate credentials IDs of credentials stored in Jenkins. Those can be used as part of an attack to capture the credentials using another vulnerability.

As of publication of this advisory, there is no fix. Learn why we announce this.

Missing permission checks in XML Job to Job DSL Plugin

SECURITY-3779 / CVE-2026-70439‍

‍Severity (CVSS): Medium

‍‍Affected plugin: xml-job-to-job-dsl‍‍

Description:

XML Job to Job DSL Plugin 0.1.13 and earlier does not perform permission checks, and makes its functionality available to users lacking Overall/Read permission. While only jobs the user has Item/Read permission for will be accessible, it does not require Item/Extended Read permission to convert their configuration.

Additionally, the plugin allows any user to invoke the conversion functionality, replacing any previously generated output in userContent.

As of publication of this advisory, there is no fix. Learn why we announce this.

Stored XSS vulnerability in Qualys Container Scanning Connector Plugin

SECURITY-3749 / CVE-2026-70440

‍‍Severity (CVSS): High‍

‍Affected plugin: qualys-cs

‍‍Description:

Qualys Container Scanning Connector Plugin 1.8.0.5 and earlier does not escape user-controlled field values in a JavaScript context.

This results in a stored cross-site scripting (XSS) vulnerability exploitable by attackers with Item/Configure permission.

As of publication of this advisory, there is no fix. Learn why we announce this.

Stored XSS vulnerability in Summary Display Plugin

SECURITY-3750 / CVE-2026-70441‍‍

Severity (CVSS): High‍

‍Affected plugin: summary_report‍

‍Description:

Summary Display Plugin 1.15 and earlier does not escape the job name in a JavaScript context in build report pages.

This results in a stored cross-site scripting (XSS) vulnerability exploitable by attackers with Item/Create or Item/Configure permission.

As of publication of this advisory, there is no fix. Learn why we announce this.

Exposure of System-scoped credentials in Google Chat Notification Plugin

SECURITY-3752 / CVE-2026-70442‍

‍Severity (CVSS): Medium

‍‍Affected plugin: google-chat-notification

‍‍Description:

Google Chat Notification Plugin 166.ve6b_de280f2e8 and earlier does not set the appropriate context for credentials lookup, allowing the use of System-scoped credentials otherwise reserved for the global configuration.

This allows attackers with Item/Configure permission to access and capture credentials they are not entitled to use.

As of publication of this advisory, there is no fix. Learn why we announce this.

Exposure of System-scoped credentials in Horreum Plugin

SECURITY-3756 / CVE-2026-70443

‍‍Severity (CVSS): Medium‍

‍Affected plugin: horreum‍

‍Description:

Horreum Plugin 0.16.162.v33b_4a_a_b_5f828 and earlier does not set the appropriate context for credentials lookup, allowing the use of System-scoped credentials otherwise reserved for the global configuration.

This allows attackers with Item/Configure permission to have Jenkins send credentials they are not entitled to use to the administrator-configured Horreum URL.

As of publication of this advisory, there is no fix. Learn why we announce this.

Missing permission check in Violation Comments to GitLab Plugin allows enumerating credentials IDs

SECURITY-3763 / CVE-2026-70444‍

‍Severity (CVSS): Medium‍

‍Affected plugin: violation-comments-to-gitlab‍

‍Description:

Violation Comments to GitLab Plugin 2.62.0 and earlier does not perform a permission check in an HTTP endpoint.

This allows attackers with Overall/Read permission to enumerate credentials IDs of credentials stored in Jenkins. Those can be used as part of an attack to capture the credentials using another vulnerability.

As of publication of this advisory, there is no fix. Learn why we announce this.

Missing permission checks in Sauce OnDemand Plugin allow enumerating credentials IDs

SECURITY-3770 / CVE-2026-70445‍

‍Severity (CVSS): Medium‍

‍Affected plugin: sauce-ondemand‍

‍Description:

Sauce OnDemand Plugin 2.2.0 and earlier does not perform permission checks in several HTTP endpoints.

This allows attackers with Overall/Read permission to enumerate credentials IDs of credentials stored in Jenkins. Those can be used as part of an attack to capture the credentials using another vulnerability.

As of publication of this advisory, there is no fix. Learn why we announce this.

Missing permission checks in CodeSonar Plugin allow enumerating credentials IDs

SECURITY-3772 / CVE-2026-70446‍

‍Severity (CVSS): Medium‍

‍Affected plugin: codesonar

‍‍Description:

CodeSonar Plugin 3.6.0 and earlier does not perform permission checks in several HTTP endpoints.

This allows attackers with Overall/Read permission to enumerate credentials IDs of credentials stored in Jenkins. Those can be used as part of an attack to capture the credentials using another vulnerability.

As of publication of this advisory, there is no fix. Learn why we announce this.

Missing permission checks in AWS CodeBuild Plugin allow enumerating credentials IDs

SECURITY-3773 / CVE-2026-70447‍‍

Severity (CVSS): Medium‍

‍Affected plugin: aws-codebuild‍

‍Description:

AWS CodeBuild Plugin 0.59 and earlier does not perform permission checks in several HTTP endpoints.

This allows attackers with Overall/Read permission to enumerate credentials IDs of credentials stored in Jenkins. Those can be used as part of an attack to capture the credentials using another vulnerability.

As of publication of this advisory, there is no fix. Learn why we announce this.

XXE vulnerability in Ivy Report Plugin

SECURITY-3899 / CVE-2026-70448

‍‍Severity (CVSS): High‍

‍Affected plugin: ivy-report‍Description:

Ivy Report Plugin 1.2 and earlier does not configure its XML parser to prevent XML external entity (XXE) attacks.

This allows attackers able to control workspace contents to have Jenkins parse a crafted Ivy report XML file that uses external entities for extraction of secrets from the Jenkins controller or server-side request forgery.

As of publication of this advisory, there is no fix. Learn why we announce this.

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Severity

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Fix

  • CloudBees Traditional Platforms should be upgraded to 2.568.2.37664
  • CloudBees Cloud Platforms should be upgraded to 2.568.2.37664
  • External Workspace Manager Plugin should be updated to version 1.4.2
  • HCL AppScan Plugin should be updated to version 1.8.4
  • Multijob Plugin should be updated to version 677.v7ffc23d6a_4c2
  • SCM-Manager Plugin should be updated to version 1.12.1
  • Webhook Secret Credentials Provider Plugin should be updated to version 32.v09c9b_522f0a_8

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Credit

  • Abdullah Hamza (notre3l) for SECURITY-3911
  • Alexander Rozanov, Innopolis University for SECURITY-3899
  • Daniel Beck, CloudBees, Inc. and independently, Sanghyeon Lee (h9e0n, https://github.com/isanghyeon) for SECURITY-3823 (1)
  • Kevin Guerroudj, CloudBees, Inc. for SECURITY-3823 (2)
  • Mykhailo Kholiev for SECURITY-3918
  • Samy Medjahed (Ap4sh) & Eliott Laurie (Ethicxz) for SECURITY-3924, SECURITY-3927, SECURITY-3930
  • Ugur Ozer, AI Risk Management for SECURITY-3907
  • Vitaly Simonovich (https://www.vitalysim.com) for SECURITY-3916
  • dyingman1 (https://github.com/dyingman1, redpoc Offensive Security Team) for SECURITY-3749, SECURITY-3750, SECURITY-3752, SECURITY-3756, SECURITY-3763, SECURITY-3768, SECURITY-3771, SECURITY-3772, SECURITY-3773, SECURITY-3779
  • dyingman1 (https://github.com/dyingman1, redpoc Offensive Security Team), and independently, Kai Aizen, SnailSploit for SECURITY-3770
  • khoadb175 for SECURITY-3888

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