PatchSiren cyber security CVE debrief

CVE-2026-50287 agenticmail CVE debrief

CVE-2026-50287 is a HIGH severity vulnerability in AgenticMail. Prior to version 0.9.27, @agenticmail/mcp exposes a Streamable HTTP transport when started with --http or MCP_HTTP=1. In that mode, the /mcp endpoint accepts requests without any HTTP authentication layer. A remote client can initialize a session and call tools directly. This issue has been patched in version 0.9.27.

Vendor: agenticmail
Product: Unknown
CVSS: HIGH 8.7
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-06-12
Original CVE updated: 2026-06-12
Advisory published: 2026-06-12
Advisory updated: 2026-06-12

Who should care

Users of AgenticMail prior to version 0.9.27 who have enabled the Streamable HTTP transport by starting with --http or setting MCP_HTTP=1.

Technical summary

The @agenticmail/mcp module in AgenticMail, when started with --http or MCP_HTTP=1, exposes an unauthenticated /mcp endpoint. This allows remote clients to initialize sessions and call tools directly without any HTTP authentication.

Defensive priority

HIGH

Recommended defensive actions

Update AgenticMail to version 0.9.27 or later.
Avoid using the --http or MCP_HTTP=1 flags to start the @agenticmail/mcp module.
Implement proper authentication and authorization for the /mcp endpoint.

Evidence notes

CVE-2026-50287 has a CVSS score of 8.7 and is classified as HIGH severity. The vulnerability was patched in version 0.9.27 of AgenticMail.

Official resources

CVE-2026-50287 was published on 2026-06-12T20:16:46.940Z and has not been modified since then.