rust-russh — security advisory

{
  "id": "2063d608d0501edc58dfd146d6516fe71bf60861d33cfb44911299e465dc0012",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-73430",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2026-73430",
    "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.",
    "evidence": "osv:UBUNTU-CVE-2026-73430",
    "products": [
      {
        "name": {
          "value": "rust-russh",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "0.57.1-2",
            "evidence": "/affected/0/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "UBUNTU-CVE-2026-73430",
      "aliases": [
        "UBUNTU-CVE-2026-73430"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "rust-russh",
            "purl": "pkg:deb/ubuntu/rust-russh?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "0.57.1-2"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-73430.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "librust-russh-dev",
                "binary_version": "0.57.1-2"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-17T13:01:03.537728541Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-73430"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2026-73430",
        "https://www.cve.org/CVERecord?id=CVE-2026-73430",
        "https://github.com/Eugeny/russh/security/advisories/GHSA-5xvq-cp9x-6p6r"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-73430",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 360909,
  "published_at": "2026-08-12T21:17:00+00:00"
}