AmazonAnalysisAWS resolves path traversal flaw in open-source Serverless MCP Server
What happened.Amazon Web Services published security bulletin 2026-164-AWS addressing a path traversal vulnerability in its open-source Serverless Model Context Protocol Server.
Why it matters.Model Context Protocol servers connect agentic AI systems directly to development environments and cloud tooling. When path traversal defects permit prompt-driven file overwrites, autonomous agents become vectors for arbitrary code execution and local credential theft. Platform teams deploying MCP servers must upgrade to version v0.2.1 immediately. Developers should run agent sidecars within isolated containers with read-only root filesystems.
The technical specifications:
- Vulnerability mechanics: Tracked as CVE-2026-116635, the flaw exists in the deployment status component of the awslabs.aws-serverless-mcp-server package.
- Traversal mechanics: The component unsafely joined the project_name parameter, allowing directory traversal sequences and absolute paths to escape the designated status folder.
- Exploit implications: Attackers prompting connected AI agents could read arbitrary JSON files or overwrite host configuration files when write permissions were enabled.
- Affected releases: All versions prior to v0.2.1 running on developer machines or containerized agent runtimes are vulnerable.
- Remediation release: AWS published package version v0.2.1, implementing strict path validation to confine all file reads and writes within the target deployment folder.