CVE-2026-73430

Russh is a Rust SSH client & server library. Prior to 0.62.4, an unauthenticated SSH client can cause a denial of service by sending SSH_MSG_KEX_ECDH_INIT with a 32-byte all-zero Q_C value. Curve25519Kex::server_dh in russh/src/kex/curve25519.rs accepts the all-zero peer public value and computes an all-zero shared secret, after which compute_exchange_hash calls encode_mpint in russh/src/kex/mod.rs and indexes beyond the end of the input while skipping leading zero bytes. The resulting panic occurs before authentication and terminates the server key-exchange task. This issue is fixed in version 0.62.4.

CVSS 3.1

5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

0.6% chance of exploitation in the next 30 days; higher than 48% of CVEs (scores of 2026-10-25)

CWE

CWE-754

Published

2026-08-12

Modified

2026-10-24

Record from

the NVD, synced 2026-10-24

Packages (OSV)

References

• https://github.com/Eugeny/russh/commit/a7fc1eb5717264e31c3c5f7dd849b73989a08f3d
• https://github.com/Eugeny/russh/releases/tag/v0.62.4
• https://github.com/Eugeny/russh/security/advisories/GHSA-5xvq-cp9x-6p6r

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