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.
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.
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.