UBUNTU-CVE-2026-73430

See a problem?
Please try reporting it to the source first.
Source
https://ubuntu.com/security/CVE-2026-73430
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73430.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-73430
Upstream
Published
2026-08-12T21:17:00Z
Modified
2026-10-17T13:01:03Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:26.10 / rust-russh

Package

Name
rust-russh
Purl
pkg:deb/ubuntu/rust-russh?arch=source&distro=stonking

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.57.1-2

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "librust-russh-dev",
            "binary_version":  "0.57.1-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73430.json"