CVE-2026-6599 langflow-ai langflow Model Context Protocol Configuration API mcp_projects.py install_mcp_config injection
Remote attackers can inject code via the X-Forwarded-For header in the MCP Configuration API, potentially executing arbitrary commands.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-6599?
CVE-2026-6599 is a medium-severity code injection vulnerability in langflow-ai langflow, published on 20 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A vulnerability was detected in langflow-ai langflow up to 1.8.3. The impacted element is the function get_client_ip/install_mcp_config of the file src/backend/base/langflow/api/v1/mcp_projects.py of the component Model Context Protocol Configuration API. Performing a manipulation of the argument X-Forwarded-For results in injection. The attack may be initiated remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Which versions are affected by CVE-2026-6599?
3 open source packages ship an affected version, including langflow.
| Package | Affected | Fixed in |
|---|---|---|
langflow PyPI | All versions to 1.8.3 | None |
langflow PyPI | All versions to 1.8.3 | None |
langflow PyPI | All versions to 1.8.3 | None |
How do I fix CVE-2026-6599?
No fix has been published for CVE-2026-6599 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-2026-6599 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-6599 exists.
Sources
Also known as GHSA-v66p-f7x3-4794, PYSEC-2026-2569.