Checkmarx Jenkins AST Plugin Compromised in KICS Supply Chain Attack

Supply chain campaign has now extended to Checkmarx’s Jenkins ecosystem, with attackers pushing a malicious Checkmarx Jenkins AST plugin to the official Jenkins Marketplace as part of the ongoing KICS/Trivy-linked compromise.

The rogue release is identified as version 2026.5.09 and includes tampered plugin artifacts, while the last known-good Jenkins AST plugin build remains 2.0.13-829.vc72453fa_1c16, released on December 17, 2025.

Checkmarx is currently preparing and validating a new, clean plugin version and has urged customers to roll back to the December 2025 or earlier builds until that update is available.

On May 9, 2026, Checkmarx disclosed that a modified version of the Checkmarx Jenkins AST plugin had been fraudulently published to the Jenkins Marketplace.

During the compromise window from 2026-05-09 01:25:00 UTC to 2026-05-10 08:47:00 UTC, a malicious build of the plugin was distributed using the following artifacts and hashes:

Marketplace	Checkmarx AST Scanner (plugins.jenkins.io)
Version	2026.5.09
File	checkmarx-ast-scanner-2026.5.09.hpi
SHA256	01ff1e56fd59a8fa525d97e670f7f297a1a204331b89b2cd4e36a9abc6419203
File	checkmarx-ast-scanner-2026.5.09.jar
SHA256	f50a96d26a5b0beb29de4127e82b2bf350c21511e5a43d286e43f798dc6cd53f
File	checkmarx-ast-scanner-2026.5.09.pom
SHA256	3ddb8967919a801b3c383e58cddceab21138134c6a26560d99e2672e86f36f2a
Window	2026-05-09 01:25:00 UTC to 2026-05-10 08:47:00 UTC

Organizations that downloaded or deployed this version within the specified timeframe should treat affected Jenkins controllers and build agents as potentially compromised and initiate full incident response.

Checkmarx Jenkins AST Plugin

The Jenkins AST plugin compromise is the latest phase in a multi-stage supply chain operation attributed to the TeamPCP threat group, which previously weaponized Aqua Security’s Trivy scanner and Checkmarx’s KICS-based ecosystem.

According to Checkmarx and third‑party analyses, the March 23, 2026 incident at Checkmarx likely originated from the Trivy supply chain attack, where TeamPCP used CI/CD credential theft to pivot into downstream software publishers.

Using stolen credentials, the attackers gained unauthorized access to Checkmarx’s GitHub environment, injected malicious code into multiple artifacts, and later leveraged that foothold to push tampered releases to Docker Hub, GitHub Actions, IDE marketplaces, and now the Jenkins plugin ecosystem.

Checkmarx reports that data was exfiltrated from its GitHub repositories on March 30, 2026, and later appeared on dark web leak sites on April 25, 2026, in a publication attributed to the LAPSUS$ cybercriminal group.

While the company stresses that customer production environments and customer data are logically and operationally separated from its internal GitHub repositories, the compromise of its development and distribution pipelines has enabled attackers to turn trusted DevSecOps tooling into an attack vector across multiple channels.

Beyond the Jenkins plugin, Checkmarx has confirmed malicious activity across several externally distributed components associated with Checkmarx One, including its public KICS Docker images, the checkmarx/ast-github-action and checkmarx/kics-github-action workflows, and multiple VS Code extensions in both the Microsoft and Open VSX marketplaces.

In each case, threat actors published credential‑stealing payloads via legitimate publisher accounts during tightly bounded time windows before the artifacts were pulled and replaced with known‑good versions.

The current investigation, supported by an external incident response firm (including Mandiant), indicates that the primary objective of the malicious code was to collect and exfiltrate secrets from CI/CD runners and developer workstations rather than deploy destructive payloads.

Checkmarx has removed the unauthorized artifacts, pinned workflows to safe SHAs, rotated exposed credentials at scale, implemented additional controls across its build and release pipelines, and locked down access to the impacted GitHub repositories while a comprehensive code audit proceeds.

Checkmarx advises all customers using the Checkmarx Jenkins AST plugin to immediately verify their deployed version and ensure they are running 2.0.13-829.vc72453fa_1c16 or an earlier, known‑safe build, avoiding the 2026.5.09 release and associated artifacts.

Organizations that interacted with any of the identified malicious versions of KICS images, GitHub Actions, or IDE extensions during the affected windows should assume potential credential exposure, rotate all associated secrets, block communication to attacker‑controlled domains and IPs, and review CI/CD and developer telemetry for signs of abuse.

Checkmarx has committed to continuing public updates as the investigation reaches its final stages and promises direct notification to customers if any evidence emerges that customer information was involved.

For now, the TeamPCP‑driven compromise of the Jenkins AST plugin underscores how rapidly a single supply chain intrusion can cascade across scanners, actions, IDEs, containers, and CI plugins turning security tooling itself into a high‑value attack surface.

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