Jenkins before LTS version 2.121.3 and weekly version 2.138 have a vulnerability exploitable by unauthenticated users. When attempting to authenticate using API token, an ephemeral user record was created to validate the token in case an external security realm was used, and the user record in Jenkins not previously saved, as (legacy) API tokens could exist without a persisted user record. This behavior could be abused to create a large number of ephemeral user records in memory. External Reference: https://jenkins.io/security/advisory/2018-08-15/#SECURITY-672
Created jenkins tracking bugs for this issue: Affects: fedora-all [bug 1620343]
OpenShift Container Platform 3.11 shipped with version 2.121.3 of Jenkins, so it was never affected by this issue.
*** Bug 1642883 has been marked as a duplicate of this bug. ***
This vulnerability had an incomplete fix in version 2.121.3. It was correctly fixed in 2.138.2: https://jenkins.io/security/advisory/2018-10-10/#SECURITY-1162
Jenkins security policy[0]: "Any security advisory related updates to Jenkins core or the plugins we include in the OpenShift Jenkins master image will only occur in the v3.11 and v4.x branches of this repository. We do support running the v3.11 version of the master image against older v3.x (as far back as v3.4) OpenShift clusters if you want to pick up Jenkins security advisory updates." [0] https://github.com/openshift/jenkins/blob/master/README.md#jenkins-security-advisories-the-master-image-from-this-repository-and-the-oc-binary