DNS Rebinding vulnerability present when running MCP Gateway in sse or streaming mode

MCP Gateway allows easy and secure running and deployment of MCP servers. In versions 0.27.0 and earlier, when MCP Gateway runs in sse or streaming transport mode, it is vulnerable to DNS rebinding. An attacker who can get a victim to visit a malicious website or be served a malicious advertisement can perform browser-based exploitation of MCP servers executing behind the gateway, including manipulating tools or other features exposed by those MCP servers. MCP Gateway is not affected when running in the default stdio mode, which does not listen on network ports. Version 0.28.0 fixes this issue.

Source published

3 Dec 2025 17:41:59 UTC

Source modified

3 Dec 2025 18:14:24 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 4.0 · 7.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:H/VA:N/SC:H/SI:H/SA:H