CVE-2026-49986 Cortex has Untrusted Project Bootstrap Code Execution via `CLAUDE_PROJECT_DIR`
An attacker can achieve arbitrary code execution by placing specific marker files in a project directory, causing the Cortex MCP server to execute malicious bootstrap code.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-49986?
CVE-2026-49986 is a high-severity code injection vulnerability in cdeust Cortex, published on 14 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
The Cortex MCP server (`neuro-cortex-memory`), a cross-platform persistent memory MCP, prior to version 3.17.1 treats the `CLAUDE_PROJECT_DIR` environment variable — automatically set by Claude Code to the currently open project directory — as a trusted Cortex developer checkout. When the `open_visualization` tool is invoked, `_find_dev_source()` resolves the user's active project directory as a candidate Cortex source root. The only validation performed by `_is_cortex_root()` is a check for the presence of an `mcp_server/` subdirectory and a `ui/unified-viz.html` file. An attacker who places these two marker files in a malicious repository can cause Cortex to execute an arbitrary `mcp_server/server/visualize_bootstrap.py` from that directory via `subprocess.run([sys.executable, ...])`, achieving code execution with the privileges of the victim's local user process. Version 3.17.1 fixes the issue.
Weakness: CWE-829
Which versions are affected by CVE-2026-49986?
3 open source packages ship an affected version, including neuro-cortex-memory.
| Package | Affected | Fixed in |
|---|---|---|
neuro-cortex-memory PyPI | All versions | 3.18.0 |
neuro-cortex-memory PyPI | All versions | 3.18.0 |
neuro-cortex-memory PyPI | All versions | 3.18.0 |
How do I fix CVE-2026-49986?
Upgrade neuro-cortex-memory to 3.18.0 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-49986 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-49986 exists.
Sources
Also known as GHSA-gvpp-v77h-5w8g, PYSEC-2026-2676.