frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow

{
  "id": "58812401fb62c4ebd34d0bdfd96f16be6963c5983d2450d652cb0370ef589805",
  "url": "https://osv.dev/vulnerability/CVE-2026-73564",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow",
    "summary": "frp is a fast reverse proxy. From 0.53.0 until 0.70.1, frp's optional SSH Tunnel Gateway in pkg/ssh/server.go parses an SSH exec channel request by adding 4 to an attacker-controlled four-byte big-endian length. A length of 0xFFFFFFFF makes the uint32 addition wrap to 3, defeats the payload bounds check, and causes payload[4:3] to panic in TunnelServer.handleNewChannel. When no authorized-keys file is configured, sshConfig.NoClientAuth permits an unauthenticated peer to reach this channel phase before the frp token is checked, so a single five-byte request terminates the frps process and drops every active tunnel. This issue is fixed in version 0.70.1.",
    "evidence": "osv:CVE-2026-73564",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-73564",
      "aliases": [
        "CVE-2026-73564",
        "GHSA-26gq-p25f-99cp",
        "GO-2026-6103"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/fatedier/frp",
              "type": "GIT",
              "events": [
                {
                  "introduced": "051299ec25638895e36779c305abf554671b4f68"
                },
                {
                  "fixed": "fa3bcca2b0c4753cd4f0e2ab189dd6a5a6a15708"
                },
                {
                  "fixed": "7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0.53.0"
                      },
                      {
                        "fixed": "0.70.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "fa3bcca2b0c4753cd4f0e2ab189dd6a5a6a15708"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v0.70.1"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.70.0",
            "v0.69.1",
            "v0.69.0",
            "v0.68.1",
            "v0.68.0",
            "v0.67.0",
            "v0.66.0",
            "v0.65.0",
            "v0.64.0",
            "v0.63.0",
            "v0.62.1",
            "v0.62.0",
            "v0.61.2",
            "v0.61.1",
            "v0.61.0",
            "v0.60.0",
            "v0.59.0",
            "v0.58.1",
            "v0.58.0",
            "v0.57.0",
            "v0.56.0",
            "v0.55.1",
            "v0.55.0",
            "v0.54.0",
            "v0.53.2",
            "v0.53.1",
            "v0.53.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-73564.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:40.459280700Z",
      "provider": "osv",
      "references": [
        "https://github.com/fatedier/frp/releases/tag/v0.70.1",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73564.json",
        "https://github.com/fatedier/frp/security/advisories/GHSA-26gq-p25f-99cp",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-73564",
        "https://github.com/fatedier/frp/commit/7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b",
        "https://github.com/fatedier/frp/pull/5428"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-129",
          "CWE-190"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73564.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-73564",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 508205,
  "published_at": "2026-08-13T17:35:46.762+00:00"
}