crates.io/rmcp CVE-2026-42559: high 8.8, EPSS 0.27%

rmcp Streamable HTTP server transport has a DNS rebinding vulnerability

Action: Upgrade rmcp to 1.4.0 or later.

cargo update -p rmcp --precise 1.4.0

Affected

Fixed versions

Sources

• osv: GHSA-89vp-x53w-74fx
• https://github.com/modelcontextprotocol/rust-sdk/security/advisories/GHSA-89vp-x53w-74fx
• https://github.com/nubo-db/dynoxide/security/advisories/GHSA-fvh2-gm75-j4j7
• https://nvd.nist.gov/vuln/detail/CVE-2026-42559
• https://github.com/modelcontextprotocol/rust-sdk/issues/815
• https://github.com/modelcontextprotocol/rust-sdk/issues/822
• https://github.com/modelcontextprotocol/rust-sdk/pull/764
• https://github.com/modelcontextprotocol/rust-sdk/commit/8e22aa2de28df5a285eed87c11cd89bf15fa90d3
• https://github.com/modelcontextprotocol/rust-sdk
• https://modelcontextprotocol.io/specification/2025-06-18/basic/transports#security-warning
• https://rustsec.org/advisories/RUSTSEC-2026-0140.html

CVE-2026-42559 · published 2026-05-06T21:55:56Z · modified 2026-09-10T03:51:04.771476338Z · JSON