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TI-2026-51548 Aliases CVE-2026-73430GHSA-5xvq-cp9x-6p6r

Russh: Pre-auth remote panic via all-zero Curve25519 peer public value (encode_mpint OOB)

Priority LOW 31CWE-754Published · 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, 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00597 48th 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
None
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-5xvq-cp9x-6p6r
  • 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-5xvq-cp9x-6p6r

Remediation

  • Fix · CNA russh (Eugeny) Fixed in 0.62.4
  • Fix · GHSA-5xvq-cp9x-6p6r russh (crates.io) Fixed in 0.62.4 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-73430
  2. 2026-10-03 Alias added: GHSA-5xvq-cp9x-6p6r

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