Checkmarks has confirmed that a modified version of the Jenkins AST plugin was published on the Jenkins Marketplace.
“If you are using the Checkmarks Jenkins AST plugin, you need to ensure that you are using version 2.0.13-829.vc72453fa_1c16 that was published on or before December 17, 2025,” the cybersecurity company said in a statement over the weekend.
At the time of writing, Checkmarks has released 2.0.13-848.v76e89de8a_053 on both GitHub and the Jenkins Marketplace, although its event update still notes that it is “in the process of publishing a new version of this plugin.” It did not disclose how the malicious plugin version was published.
This development is the latest attack by TeamPCP targeting Checkmarks. This comes just weeks after the notorious cybercrime group was blamed for the compromise of its KICS Docker image, two VS Code extensions, and a GitHub Actions workflow to push credential-stealing malware.
In turn, the breach resulted in the brief compromise of the Bitwarden CLI npm package to serve up a similar stealer, which can trace a wide range of developer secrets.
TeamPCP has been linked to a series of breaches since March 2026 as part of a broader campaign that exploited implicit trust in the software supply chain to spread its malware and expand its reach.
According to details shared by security researcher Adnan Khan and SOCRadar, TeamPCP has gained unauthorized access to the plugin’s GitHub repository and renamed it “Checkmarks-Fully-Hacked-By-TeamPCP-And-Their-Customers-Should-Cancel-Now.”
The defaced repository was also updated to include the description: “Checkmarks again fails to rotate secrets. With love – TeamPCP.”
“The fact that TeamPCP is back inside the Checkmarks system just a few weeks later points to one of two possibilities: either the initial fix was incomplete and the credentials were not fully rotated, or the group retained a foothold that was not identified during the March response,” SOCRadar said.
“The second Checkmarks event coming soon shows that the group is actively monitoring re-entry points, testing the depth of previous corrections, and taking advantage of any gaps.”
