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High · 7.2 Public exploit CVE-2026-44246 EUVD-2026-29841

nnU-Net: Agentic workflow injection in `.github/workflows/issue-triage.yml` of `MIC-DKFZ/nnUNet`

Published May 12, 2026 · Updated May 13, 2026 · Assigned by GitHub_M

Description

nnU-Net is a semantic segmentation framework that automatically adapts its pipeline to a dataset. Prior to 2.4.1, the nnU-Net Issue Triage workflow in .github/workflows/issue-triage.yml is vulnerable to Agentic Workflow Injection. The workflow sets allowed_non_write_users: ${{ github.event.issue.user.login }}, which means any logged-in GitHub user who opens an issue can reach this agentic workflow with attacker-controlled content. Untrusted issue title and body content are embedded directly into the prompt of anthropics/claude-code-action, and the workflow then runs a command-capable Claude agent with permission to comment on and relabel the current issue via gh. Because this workflow is triggered automatically on issues.opened, an external attacker can submit a crafted issue that steers the agent beyond its intended issue-triage purpose and influences authenticated issue actions. This vulnerability is fixed in 2.4.1.

Affected products

VendorProductAffectedFixed
MIC-DKFZ nnUNet < 2.4.1 —

Public exploits

Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.

Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.

GitHub 2 repositories

  • Reproducible vulnerable/fixed fixtures for agentic workflow injection in GitHub Actions (CVE-2026-44246), plus measured detector coverage

  • pvharmo2/gha-lab-733c168b88 ★ 0 · Sep 6, 2026

    Authorized security-research lab reproducing CVE-2026-44246 (GHSA-63mx-j37w-gh59): prompt injection via verbatim issue title/body inlining into the claude-code-action triage agent in nnU-Net's issue-…

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

References