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TI-2026-51547 Aliases CVE-2026-73429GHSA-g9hv-x236-4qp3

Russh: client wrong-length X25519 `clone_from_slice` panic (pre-auth DoS)

Priority MEDIUM 63CWE-704Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · None · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

Russh is a Rust SSH client & server library. Prior to 0.62.4, a malicious SSH server can crash a russh client session with a malformed KEX_ECDH_REPLY containing a server ephemeral value that is not 32 bytes long. The client-side Curve25519Kex::compute_shared_secret function in russh/src/kex/curve25519.rs passes the decoded exchange.server_ephemeral value to clone_from_slice without validating its length, causing a deterministic panic before the server host key is verified. The panic terminates the spawned client session task and surfaces as a JoinError, while the embedding process normally remains running. This issue is fixed in version 0.62.4.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00507 43rd percentileScored 2026-11-07
Fix Fixed russh (Eugeny): 0.62.4russh (crates.io): 0.62.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Eugenyrusshbefore 0.62.40.62.4Patch availableCNA
—russh (crates.io)before 0.62.40.62.4Patch availableGHSA-g9hv-x236-4qp3
  • russh VendorEugeny Affected before 0.62.4 Fixed in 0.62.4 Patch available CNA
  • russh (crates.io) Vendor— Affected before 0.62.4 Fixed in 0.62.4 Patch available GHSA-g9hv-x236-4qp3

Remediation

  • Fix · CNA russh (Eugeny) Fixed in 0.62.4
  • Fix · GHSA-g9hv-x236-4qp3 russh (crates.io) Fixed in 0.62.4 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-73429
  2. 2026-10-03 Alias added: GHSA-g9hv-x236-4qp3

References

Other 4

  • TI-2026-65512 russh: Client-side channel-scoped Handler callbacks fire for channel IDs the client never opened CVSS 3.1HIGH 7.5
  • TI-2026-35550 Russh: SSH message fields were decoded through allocation-first parsers before field-specific bounds CVSS 3.1HIGH 7.5
  • TI-2026-34331 Russh: Post-decompression SSH packet size was not bounded, allowing remote oversized compressed packets CVSS 3.1HIGH 7.5
  • TI-2026-34308 Resource allocation without limits in Eugeny russh CVSS 3.1HIGH 7.5
  • TI-2025-16084 Tabby has a TCC Bypass via Misconfigured Node Fuses CVSS 4.0HIGH 8.6
  • TI-2024-36991 Tabby has a TCC Bypass via Unnecessary Permissive Entitlements in Tabby CVSS 4.0HIGH 8.6
See all 25 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences