CVE-2026-102824 (GCVE-0-2026-102824)

Vulnerability from cvelistv5 – Published: 2026-09-29 18:27 – Updated: 2026-09-29 18:27
VLAI
Title
Russh: Missing X25519 zero-point validation in hybrid ML-KEM key exchange
Summary
Russh is a Rust SSH client and server library. Prior to 0.63.0, the hybrid ML-KEM 768 and X25519 implementation in russh/src/kex/hybrid_mlkem.rs accepts an all-zero 32-byte peer X25519 public key in both server_dh and compute_shared_secret, forcing the X25519 contribution to the combined shared secret to zero. A malicious SSH peer can therefore make the combined secret depend only on ML-KEM, defeating the hybrid exchange's intended fallback protection if ML-KEM is later weakened. This issue is fixed in version 0.63.0.
Severity
4.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CWE
  • CWE-327 - Use of a Broken or Risky Cryptographic Algorithm
Assigner
References
Impacted products
Vendor Product Version CPE status
Eugeny russh Affected: < 0.63.0
guessed Create a notification for this product.
Show details on NVD website
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{
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      "affected": [
        {
          "product": "russh",
          "vendor": "Eugeny",
          "versions": [
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        }
      ],
      "metrics": [
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            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-327",
              "description": "CWE-327: Use of a Broken or Risky Cryptographic Algorithm",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-29T18:27:41.650Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/Eugeny/russh/security/advisories/GHSA-w3jg-pjxf-73p4",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/Eugeny/russh/security/advisories/GHSA-w3jg-pjxf-73p4"
        },
        {
          "name": "https://github.com/Eugeny/russh/commit/8da8967f196472576b1565d518a0ed60fce60f0c",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Eugeny/russh/commit/8da8967f196472576b1565d518a0ed60fce60f0c"
        },
        {
          "name": "https://github.com/Eugeny/russh/releases/tag/v0.63.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Eugeny/russh/releases/tag/v0.63.0"
        }
      ],
      "source": {
        "advisory": "GHSA-w3jg-pjxf-73p4",
        "discovery": "UNKNOWN"
      },
      "title": "Russh: Missing X25519 zero-point validation in hybrid ML-KEM key exchange"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-102824",
    "datePublished": "2026-09-29T18:27:41.650Z",
    "dateReserved": "2026-09-29T17:25:25.265Z",
    "dateUpdated": "2026-09-29T18:27:41.650Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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          {
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              {
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                "vendor": "Eugeny",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 0.63.0"
                  }
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            "source": "security-advisories@github.com"
          }
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Russh is a Rust SSH client and server library. Prior to 0.63.0, the hybrid ML-KEM 768 and X25519 implementation in russh/src/kex/hybrid_mlkem.rs accepts an all-zero 32-byte peer X25519 public key in both server_dh and compute_shared_secret, forcing the X25519 contribution to the combined shared secret to zero. A malicious SSH peer can therefore make the combined secret depend only on ML-KEM, defeating the hybrid exchange\u0027s intended fallback protection if ML-KEM is later weakened. This issue is fixed in version 0.63.0."
          }
        ],
        "id": "CVE-2026-102824",
        "lastModified": "2026-09-29T19:17:24.673",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 4.3,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
                "version": "3.1"
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            "url": "https://github.com/Eugeny/russh/commit/8da8967f196472576b1565d518a0ed60fce60f0c"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/Eugeny/russh/releases/tag/v0.63.0"
          },
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            "source": "security-advisories@github.com",
            "url": "https://github.com/Eugeny/russh/security/advisories/GHSA-w3jg-pjxf-73p4"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Deferred",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-327"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-29T19:27:34+00:00",
      "cve": "CVE-2026-102824",
      "id": "CVE-2026-102824",
      "initial_release_date": "2026-09-29T18:27:41.650000+00:00",
      "product_status:known_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "russh: russh: Cryptographic fallback bypass via missing public key validation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-102824.json",
      "version": "3"
    }
  }
}



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