CVE-2026-44246 nnU-Net: Agentic workflow injection in `.github/workflows/issue-triage.yml` of `MIC-DKFZ/nnUNet`
Attackers can inject malicious prompts into GitHub Actions workflows via issue content, leading to unauthorized code execution and privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-44246?
CVE-2026-44246 is a high-severity code injection vulnerability in MIC-DKFZ nnUNet, published on 12 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-44246?
It affects 1 product.
Products include Dkfz Nnu-Net.
How do I fix CVE-2026-44246?
No fix has been published for CVE-2026-44246 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-44246 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44246 exists.
Public exploit code: 2 proofs of concept on GitHub.
Sources
Also known as GHSA-63mx-j37w-gh59.