Improper Protection of Alternate Path Affecting awslabs.aws-api-mcp-server package, versions [0.2.14,1.3.9)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-AWSLABSAWSAPIMCPSERVER-15763420
- published25 Mar 2026
- disclosed16 Mar 2026
- creditVaronis Threat Labs
Introduced: 16 Mar 2026
CVE-2026-4270 (opens in a new tab)How to fix?
Upgrade awslabs.aws-api-mcp-server to version 1.3.9 or higher.
Overview
awslabs.aws-api-mcp-server is a Model Context Protocol (MCP) server for interacting with AWS
Affected versions of this package are vulnerable to Improper Protection of Alternate Path through the AWS CLI shorthand parser in aws_api_mcp_server/core/aws/services.py. An attacker can read arbitrary local files in the MCP client application context by supplying file:// or fileb:// shorthand parameter values such as @=-style file references, when file access is intended to be disabled or limited to a workdir.