Blue Ocean Plugin 1.23.2 and earlier provides an undocumented feature flag, blueocean.features.GIT_READ_SAVE_TYPE, that when set to the value clone allows an attacker with Item/Configure or Item/Create permission to read arbitrary files on the Jenkins controller file system.

Blue Ocean Plugin 1.23.3 no longer includes this feature and redirects existing usage to a safer alternative.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-2254
• https://www.jenkins.io/security/advisory/2020-09-16/#SECURITY-1956
• http://www.openwall.com/lists/oss-security/2020/09/16/3
• jenkinsci/blueocean-plugin@f0dd4b6