Quick answers
- Is CVE-2026-73430 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-73430 being exploited in the wild.
- How severe is CVE-2026-73430?
- Medium severity, with a CVSS score of 5.3, published 12 August 2026.
- Which products and versions are affected?
- russh (crates.io) SEMVER:introduced=0,fixed=0.62.4.
- Is there a fix for CVE-2026-73430?
- Yes. russh (crates.io): upgrade to 0.62.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-73430 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-73430?
- Check whether you run russh (crates.io) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- russh (crates.io): upgrade to 0.62.4 or later
cargo update -p russh
Technical details
The vulnerability is a denial-of-service (panic) in Russh's Curve25519 key exchange (KEX) implementation. When a server receives SSH_MSG_KEX_ECDH_INIT with an all-zero Q_C (peer public key) value, the code fails to validate this invalid state. The Curve25519Kex::server_dh function computes a shared secret that is all zeros, then compute_exchange_hash calls encode_mpint which attempts to skip leading zero bytes and indexes out of bounds, causing a panic. This occurs before authentication, meaning any unauthenticated SSH client on the network can trigger it. The vulnerability was fixed in version 0.62.4 by validating Curve25519 keys and correcting mpint encoding logic.
Affected products
- Eugeny Russh before 0.62.4
Identifiers
- CVE-2026-73430
- GHSA-5xvq-cp9x-6p6r
Timeline
- 2026-08-12: disclosed: CVE-2026-73430 published
- 2026-07-22: patched: Fix released in version 0.62.4