A data modification vulnerability exists in Jenkins 2.153 and earlier, LTS 2.138.3 and earlier in User.java, IdStrategy.java that allows attackers to submit crafted user names that can cause an improper migration of user record storage formats, potentially preventing the victim from logging into Jenkins.
A denial of service vulnerability exists in Jenkins 2.153 and earlier, LTS 2.138.3 and earlier in CronTab.java that allows attackers with Overall/Read permission to have a request handling thread enter an infinite loop.