Jenkins Convert To Pipeline Plugin 1.0 and earlier uses basic string concatenation to convert Freestyle projects' Build Environment, Build Steps, and Post-build Actions to the equivalent Pipeline step invocations.

This allows attackers able to configure Freestyle projects to prepare a crafted configuration that injects Pipeline script code into the (unsandboxed) Pipeline resulting from a conversion by Convert To Pipeline Plugin. If an administrator converts the Freestyle project to a Pipeline, the script will be pre-approved.

References

• https://nvd.nist.gov/vuln/detail/CVE-2023-28677
• https://www.jenkins.io/security/advisory/2023-03-21/#SECURITY-2966