What’s Vulnerable › Vulnerabilities

CVE-2026-87913: Missing S3 bucket ownership verification in the AWS Security Agent MCP server

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-10 · updated 2026-09-10
• Weakness: CWE-283

Description

A missing S3 bucket ownership verification in the AWS Security Agent MCP server before 0.2.0 version might allow remote attackers to obtain the private source archive of a scanned workspace, including credentials and infrastructure state contained in that archive, via a pre-registered storage bucket whose name is derived from a publicly known account identifier. To remediate this issue, users should upgrade to version 0.2.0. Users should also verify that the scan output bucket in their account is owned by their own account, because upgrading does not release a bucket name that a third party has already registered.

Affected products

• AWS Security Agent MCP server: from 0.1.0 through 0.1.5

References

• https://aws.amazon.com/security/security-bulletins/2026-105-aws/
• https://github.com/awslabs/mcp/security/advisories/GHSA-3jxw-vj8m-8x77
• https://pypi.org/project/awslabs.security-agent-mcp-server/0.2.0/?refid=d8ec3b19-0f37-4f8c-8c12-189f913e205c

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