Summary
A critical code injection vulnerability in mcp-remote may allow a remote attacker to cause arbitrary code execution through processing associated with the getServerUrlHash function.
The issue affects versions 0.1.16 through 0.1.38 when attacker-controlled input can reach the vulnerable utility logic.
Affected context
The vulnerability occurs in the src/lib/utils.ts component of mcp-remote, specifically around the getServerUrlHash function. Deployments using affected versions may be at risk when remote input is processed by this function without sufficient separation between data and executable behavior.
Exploit preconditions
- Attack surface: Network-accessible mcp-remote functionality that invokes the affected utility
- Required access: Ability to submit or influence input processed by
getServerUrlHash - Trigger point: Handling of server URL or related hash-processing logic
- Why exploitation is possible: Attacker-controlled data may reach an execution-capable code path without adequate neutralization or contextual validation
Why this happens
The underlying defect is an unsafe code-generation or evaluation pattern in utility logic that processes externally influenced values. When data is incorporated into executable behavior rather than handled strictly as data, an attacker may be able to alter the resulting operation and execute unintended code. This maps to CWE-94: Improper Control of Generation of Code ('Code Injection').
Potential impact
- A remote attacker may execute arbitrary code in the mcp-remote process context
- The attacker could access application data and runtime credentials
- The affected host or container may be modified or used for further compromise
- Service availability could be disrupted
- Connected systems may be exposed depending on process privileges and network access
General mitigation guidance
Mitigation generally focuses on ensuring that server URLs, hashes, and related values remain data-only throughout processing.
Common defensive patterns include:
- Replacing dynamic evaluation or code-generation behavior with ordinary parsing and comparison
- Applying strict allowlists and canonical validation to accepted URL formats
- Treating all network-derived values as untrusted, including values that appear structurally valid
- Running the process with least-privilege permissions and restricted filesystem and network access
- Isolating remote-server integrations from sensitive credentials and administrative interfaces
- Enforcing dependency and security review policies for code paths that process remote input
How teams detect issues like this
Organizations can look for:
- Static-analysis findings involving dynamic evaluation, runtime compilation, shell execution, or string-to-code conversion
- Code-review signals where URL, hash, or network input is interpolated into executable expressions
- Tests that submit malformed, unexpected, and boundary-case server identifiers
- Runtime monitoring for unexpected child processes, outbound connections, or changes to protected files
- Dependency and policy checks covering affected package versions and security-sensitive utility functions
Automated code-review tools may help identify execution-capable APIs and missing input validation.
