MIC-DKFZ nnUNet up to 2.4.0 issue-triage.yml allowed_non_write_users injection

Summaryinfo

A vulnerability, which was classified as critical, has been found in MIC-DKFZ nnUNet up to 2.4.0. Affected by this vulnerability is the function allowed_non_write_users of the file github/workflows/issue-triage.yml. This manipulation causes Remote Code Execution. This vulnerability is registered as CVE-2026-44246. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in MIC-DKFZ nnUNet up to 2.4.0. Affected by this vulnerability is the function allowed_non_write_users of the file github/workflows/issue-triage.yml. The manipulation with an unknown input leads to a remote code execution vulnerability. The CWE definition for the vulnerability is CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-44246 since 05/05/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1055 for this issue.

Upgrading to version 2.4.1 eliminates this vulnerability.

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Productinfo

Vendor

• MIC-DKFZ

Name

• nnUNet

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4.0

Website

• Product: https://github.com/MIC-DKFZ/nnUNet/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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