A denial of service vulnerability exists in Jenkins 2.137 and earlier, 2.121.2 and earlier in BasicAuthenticationFilter.java, BasicHeaderApiTokenAuthenticator.java that allows attackers to create ephemeral in-memory user records by attempting to log in using invalid credentials.
Severity
CVSS 3.0
7.5 high
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
1.7% chance of exploitation in the next 30 days; higher than 76% of CVEs (scores of 2026-10-31)