Jenkins before 2.107 and Jenkins LTS before 2.89.4 did not properly prevent specifying relative paths that escape a base directory for URLs accessing plugin resource files. This allowed users with Overall/Read permission to download files from the Jenkins master they should not have access to. On Windows, any file accessible to the Jenkins master process could be downloaded. On other operating systems, any file within the Jenkins home directory accessible to the Jenkins master process could be downloaded.

An improper input validation vulnerability exists in Jenkins versions 2.106 and earlier, and LTS 2.89.3 and earlier, that allows an attacker to access plugin resource files in the META-INF and WEB-INF directories that should not be accessible, if the Jenkins home directory is on a case-insensitive file system.

An improper authorization vulnerability exists in Jenkins versions 2.106 and earlier, and LTS 2.89.3 and earlier, that allows an attacker to have Jenkins submit HTTP GET requests and get limited information about the response.

Jenkins versions 2.56 and earlier as well as 2.46.1 LTS and earlier are vulnerable to an issue in the Jenkins user database authentication realm: create an account if signup is enabled; or create an account if the victim is an administrator, possibly deleting the existing default admin user in the process and allowing a wide variety of impacts.

Jenkins versions 2.56 and earlier as well as 2.46.1 LTS and earlier are vulnerable to an XStream: Java crash when trying to instantiate void/Void.

Jenkins versions 2.56 and earlier as well as 2.46.1 LTS and earlier are vulnerable to a login command which allowed impersonating any Jenkins user. The `login` command available in the remoting-based CLI stored the encrypted user name of the successfully authenticated user in a cache file used to authenticate further commands. Users with sufficient permission to create secrets in Jenkins, and download their encrypted values (e.g. with Job/Configure permission), were able to impersonate any other Jenkins user on the same instance.

Jenkins versions 2.56 and earlier as well as 2.46.1 LTS and earlier are vulnerable to an unauthenticated remote code execution. An unauthenticated remote code execution vulnerability allowed attackers to transfer a serialized Java `SignedObject` object to the Jenkins CLI, that would be deserialized using a new `ObjectInputStream`, bypassing the existing blacklist-based protection mechanism. We're fixing this issue by adding `SignedObject` to the blacklist. We're also backporting the new HTTP CLI protocol from Jenkins 2.54 to LTS 2.46.2, and deprecating the remoting-based (i.e. Java serialization) CLI protocol, disabling it by default.

The Jenkins 2.73.1 and earlier, 2.83 and earlier default form control for passwords and other secrets, <f:password/>, supports form validation (e.g. for API keys). The form validation AJAX requests were sent via GET, which could result in secrets being logged to a HTTP access log in non-default configurations of Jenkins, and made available to users with access to these log files. Form validation for <f:password/> is now always sent via POST, which is typically not logged.

The Jenkins 2.73.1 and earlier, 2.83 and earlier remote API at /job/(job-name)/api contained information about upstream and downstream projects. This included information about tasks that the current user otherwise has no access to, e.g. due to lack of Item/Read permission. This has been fixed, and the API now only lists upstream and downstream projects that the current user has access to.

The Jenkins 2.73.1 and earlier, 2.83 and earlier remote API at /queue/item/(ID)/api showed information about tasks in the queue (typically builds waiting to start). This included information about tasks that the current user otherwise has no access to, e.g. due to lack of Item/Read permission. This has been fixed, and the API endpoint is now only available for tasks that the current user has access to.

The remote API in Jenkins 2.73.1 and earlier, 2.83 and earlier at /computer/(agent-name)/api showed information about tasks (typically builds) currently running on that agent. This included information about tasks that the current user otherwise has no access to, e.g. due to lack of Item/Read permission. This has been fixed, and the API now only shows information about accessible tasks.

Jenkins 2.73.1 and earlier, 2.83 and earlier bundled a version of the commons-httpclient library with the vulnerability CVE-2012-6153 that incorrectly verified SSL certificates, making it susceptible to man-in-the-middle attacks. This library is widely used as a transitive dependency in Jenkins plugins. The fix for CVE-2012-6153 was backported to the version of commons-httpclient that is bundled in core and made available to plugins.

Jenkins 2.73.1 and earlier, 2.83 and earlier provides information about Jenkins user accounts which is generally available to anyone with Overall/Read permissions via the /user/(username)/api remote API. This included e.g. Jenkins users' email addresses if the Mailer Plugin is installed. The remote API now no longer includes information beyond the most basic (user ID and name) unless the user requesting it is a Jenkins administrator.

Jenkins 2.73.1 and earlier, 2.83 and earlier bundled a version of the commons-fileupload library with the denial-of-service vulnerability known as CVE-2016-3092. The fix for that vulnerability has been backported to the version of the library bundled with Jenkins.

Jenkins 2.73.1 and earlier, 2.83 and earlier users with permission to create or configure agents in Jenkins could configure a launch method called 'Launch agent via execution of command on master'. This allowed them to run arbitrary shell commands on the master node whenever the agent was supposed to be launched. Configuration of this launch method now requires the Run Scripts permission typically only granted to administrators.

Jenkins 2.88 and earlier; 2.73.2 and earlier Autocompletion suggestions for text fields were not escaped, resulting in a persisted cross-site scripting vulnerability if the source for the suggestions allowed specifying text that includes HTML metacharacters like less-than and greater-than characters.

Jenkins versions 2.88 and earlier and 2.73.2 and earlier stores metadata related to 'people', which encompasses actual user accounts, as well as users appearing in SCM, in directories corresponding to the user ID on disk. These directories used the user ID for their name without additional escaping, potentially resulting in problems like overwriting of unrelated configuration files.

A race condition during Jenkins 2.94 and earlier; 2.89.1 and earlier startup could result in the wrong order of execution of commands during initialization. There is a very short window of time after startup during which Jenkins may no longer show the 'Please wait while Jenkins is getting ready to work' message but Cross-Site Request Forgery (CSRF) protection may not yet be effective.

Jenkins through 2.93 allows remote authenticated administrators to conduct XSS attacks via a crafted tool name in a job configuration form, as demonstrated by the JDK tool in Jenkins core and the Ant tool in the Ant plugin, aka SECURITY-624.

Jenkins before 1.586 does not set the HttpOnly flag in a Set-Cookie header for session cookies when run on Tomcat 7.0.41 or later, which makes it easier for remote attackers to obtain potentially sensitive information via script access to cookies.