GHSA-g9hv-x236-4qp3: Russh: client wrong-length X25519 `clone_from_slice` panic (pre-auth DoS)

July 24, 2026

A malicious SSH server can crash a russh client session with a single malformed key-exchange reply, causing a pre-authentication Denial-of-Service before the server host key is verified. The embedding process itself stays up, but the connection is killed deterministically.

References

github.com/Eugeny/russh/commit/a7fc1eb5717264e31c3c5f7dd849b73989a08f3d
github.com/Eugeny/russh/releases/tag/v0.62.4
github.com/Eugeny/russh/security/advisories/GHSA-g9hv-x236-4qp3
github.com/advisories/GHSA-g9hv-x236-4qp3

Code Behaviors & Features

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