Vulnerability Details CVE-2026-4270
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.
To remediate this issue, users should upgrade to version 1.3.9.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 3.0%
CVSS Severity
CVSS v3 Score 5.5
References
Products affected by CVE-2026-4270
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cpe:2.3:a:amazon:aws_api_mcp_server:0.2.14
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cpe:2.3:a:amazon:aws_api_mcp_server:0.3.0
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cpe:2.3:a:amazon:aws_api_mcp_server:0.3.1
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cpe:2.3:a:amazon:aws_api_mcp_server:0.3.2
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cpe:2.3:a:amazon:aws_api_mcp_server:0.3.3
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cpe:2.3:a:amazon:aws_api_mcp_server:0.3.4
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cpe:2.3:a:amazon:aws_api_mcp_server:1.0.0
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cpe:2.3:a:amazon:aws_api_mcp_server:1.0.1
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cpe:2.3:a:amazon:aws_api_mcp_server:1.0.2
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cpe:2.3:a:amazon:aws_api_mcp_server:1.1.0
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cpe:2.3:a:amazon:aws_api_mcp_server:1.1.1
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cpe:2.3:a:amazon:aws_api_mcp_server:1.1.2
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cpe:2.3:a:amazon:aws_api_mcp_server:1.1.3
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cpe:2.3:a:amazon:aws_api_mcp_server:1.1.4
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cpe:2.3:a:amazon:aws_api_mcp_server:1.1.5
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cpe:2.3:a:amazon:aws_api_mcp_server:1.1.6
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cpe:2.3:a:amazon:aws_api_mcp_server:1.1.7
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cpe:2.3:a:amazon:aws_api_mcp_server:1.1.8
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cpe:2.3:a:amazon:aws_api_mcp_server:1.2.0
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cpe:2.3:a:amazon:aws_api_mcp_server:1.2.1
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cpe:2.3:a:amazon:aws_api_mcp_server:1.2.2
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cpe:2.3:a:amazon:aws_api_mcp_server:1.2.3
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cpe:2.3:a:amazon:aws_api_mcp_server:1.3.0
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cpe:2.3:a:amazon:aws_api_mcp_server:1.3.1
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cpe:2.3:a:amazon:aws_api_mcp_server:1.3.2
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cpe:2.3:a:amazon:aws_api_mcp_server:1.3.3
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cpe:2.3:a:amazon:aws_api_mcp_server:1.3.4
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cpe:2.3:a:amazon:aws_api_mcp_server:1.3.5
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cpe:2.3:a:amazon:aws_api_mcp_server:1.3.6
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cpe:2.3:a:amazon:aws_api_mcp_server:1.3.7
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cpe:2.3:a:amazon:aws_api_mcp_server:1.3.8