{"cve":"CVE-2026-4270","nvd":{"published":"2026-03-16T17:16:32.270","modified":"2026-06-17T10:56:20.093","status":"Analyzed","description":"Improper Protection of Alternate Path exists in the no-access and workdir feature of the AWS API MCP Server versions >= 0.2.14 and < 1.3.9 on all platforms may allow the bypass of intended file access restriction and expose arbitrary local file contents in the MCP client application context.\n\nTo remediate this issue, users should upgrade to version 1.3.9.","cvss_v4":{"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","score":6.8},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","score":5.5},"cwes":["CWE-424"],"references":["https://aws.amazon.com/security/security-bulletins/2026-007-AWS/","https://pypi.org/project/awslabs.aws-api-mcp-server/1.3.9/"],"products":["amazon:aws_api_mcp_server"],"source":"nvd","synced_at":"2026-10-19T22:26:19.218427112+00:00"},"epss":{"cve":"CVE-2026-4270","score":0.00133,"percentile":0.02801,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-2cpp-j2fc-qhp7","url":"https://osv.dev/vulnerability/GHSA-2cpp-j2fc-qhp7","summary":"AWS API MCP File Access Restriction Bypass","modified":"2026-06-08T23:30:20.315711802Z","packages":[{"ecosystem":"PyPI","name":"awslabs-aws-api-mcp-server","purl":"pkg:pypi/awslabs-aws-api-mcp-server","ranges":[">=0.2.14 <1.3.9"],"fixed":["1.3.9"]},{"ecosystem":"PyPI","name":"awslabs-aws-api-mcp-server","purl":"pkg:pypi/awslabs-aws-api-mcp-server","ranges":[">=0.2.14 <1.3.9"],"fixed":["1.3.9"]}]},{"id":"PYSEC-2026-162","url":"https://osv.dev/vulnerability/PYSEC-2026-162","summary":"","modified":"2026-06-10T17:00:36.402824571Z","packages":[{"ecosystem":"PyPI","name":"awslabs-aws-api-mcp-server","purl":"pkg:pypi/awslabs-aws-api-mcp-server","ranges":[">=0.2.14 <1.3.9"],"fixed":["1.3.9"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}