EUVD-2026-57625
GHSA-5xvq-cp9x-6p6r
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Pre-auth network attack on default config requires no privileges; only the per-connection KEX task crashes, so A:L not A:H.
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Lifecycle Timeline
4DescriptionCVE.org
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.
AnalysisAI
Unauthenticated remote denial of service in the Russh SSH library (versions ≤ 0.62.3) allows any network attacker to crash individual server key-exchange sessions by sending a single SSH_MSG_KEX_ECDH_INIT packet containing a 32-byte all-zero Curve25519 public key. The defect triggers under the default server configuration - no special deployment required - causing a Rust bounds-check panic in encode_mpint before host-key signature verification ever occurs. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires only network access to the SSH port of a server built on Russh using its default configuration (Config::default(), which includes curve25519-sha256 via Preferred::DEFAULT). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L, score 5.3) accurately reflects the attack surface: fully unauthenticated, network-reachable on any default Russh server, with low attack complexity since a single malformed packet triggers the panic. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker opens a TCP connection to any exposed Russh-based SSH server, completes the SSH version string exchange, and sends a single SSH_MSG_KEX_ECDH_INIT packet with the 32-byte Q_C field set to all zeros. The server's key-exchange task panics immediately upon attempting to encode the resulting all-zero shared secret, terminating the connection before authentication. … |
| Remediation | Upgrade Russh to version 0.62.4 or later, confirmed as the vendor-released patch at https://github.com/Eugeny/russh/releases/tag/v0.62.4 and applied via commit a7fc1eb5717264e31c3c5f7dd849b73989a08f3d (https://github.com/Eugeny/russh/commit/a7fc1eb5717264e31c3c5f7dd849b73989a08f3d); the fix adds explicit zero-point rejection in curve25519.rs and corrects the all-zero mpint encoding in mod.rs. … Detailed patch versions, workarounds, and compensating controls in full report. |
Threat intelligence, references, and detailed analysis are available after sign-in.
The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remot
Russh is a Rust SSH client & server library. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable,
russh is a Rust SSH client and server library. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploita
Denial-of-service in russh's Curve25519 key exchange client path allows any malicious SSH server to crash a connecting r
Pre-authentication denial-of-service in russh SSH server library allows remote attackers to crash servers implementing k
Denial of service in Russh (Rust SSH client/server library) versions 0.34.0 through 0.60.x allows remote SSH peers to tr
Denial of service in Russh (versions 0.37.0-0.60.x), a Rust SSH client and server library, allows a malicious SSH server
Resource exhaustion in Russh's SSH server identification-string reader allows unauthenticated remote attackers to hold c
Russh is a Rust SSH client & server library. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitabl
Same technique Denial Of Service
View allShare
External POC / Exploit Code
Leaving vuln.today