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archivevulnerability · 16 Sep 2026 · 22:13 UTC

GHSA-9pj6-vhgr-3mwh: RMCP: Unauthenticated permanent session-table leak in rmcp Streamable HTTP server transport leads to remote de

VULNCVE-2026-63128source · GTH
HIGHHigh-risk vulnerability — CVSS 7.5

last 60 dispatches · spectrum

### Summary An unauthenticated remote attacker can leak one entry per HTTP request out of the in-memory session table of `LocalSessionManager` by sending a well-formed JSON-RPC `POST` that is *not* an `InitializeRequest`. The Streamable HTTP server's `handle_post` allocates the session **before** it validates the body, then early-returns on the validation failure without calling `close_session`. …

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