rsync 3.1.0 < 3.5.0 Access Control Bypass via DNS Resolution Failure

{
  "id": "ce98d9c6e8fad40722277c18a6e58c4475f21b8761c63c559b94b93fc3b386a4",
  "url": "https://osv.dev/vulnerability/CVE-2026-70452",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "rsync 3.1.0 < 3.5.0 Access Control Bypass via DNS Resolution Failure",
    "summary": "rsync 3.1.0 before 3.5.0 contains an access control bypass vulnerability that allows remote attackers to circumvent hosts deny rules by inducing DNS resolution failures during hostname-based access control evaluation. When a DNS lookup for a hostname-based deny rule fails, the daemon skips the rule rather than defaulting to a deny decision, enabling attackers who can trigger DNS failures to bypass module-level IP access controls and gain unauthorized access to restricted module file trees.",
    "evidence": "osv:CVE-2026-70452",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-70452",
      "aliases": [
        "CVE-2026-70452",
        "GHSA-6692-28cx-wpqq"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/rsyncproject/rsync",
              "type": "GIT",
              "events": [
                {
                  "introduced": "bc58313bf7f42f0993f7279299e8137e0f14f01c"
                },
                {
                  "fixed": "471e17dc0d68233db84db11be82c9f62f4661214"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "3.1.0"
                      },
                      {
                        "last_affected": "3.4.4"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "471e17dc0d68233db84db11be82c9f62f4661214"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v3.5.0"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.4.3",
            "v3.4",
            "v3.2.7",
            "v3.4.1",
            "v3.4.2",
            "v3.4.0",
            "v3.3.0",
            "v3.3.0pre1",
            "v3.2.7pre1",
            "v3.2.6",
            "v3.2.5",
            "v3.2.5pre2",
            "v3.2.5pre1",
            "v3.2.4",
            "v3.2.4pre4",
            "v3.2.4pre3",
            "v3.2.4pre2",
            "v3.2.4pre1",
            "v3.2.3",
            "v3.2.3pre1",
            "v3.2.2",
            "v3.2.2pre3",
            "v3.2.2pre2",
            "v3.2.2pre1",
            "v3.2.1",
            "v3.2.1pre1",
            "v3.2.0",
            "v3.2.0pre3",
            "v3.2.0pre2",
            "v3.2.0pre1",
            "v3.1.3",
            "v3.1.3pre1",
            "v3.1.2",
            "v3.1.2pre1",
            "v3.1.1",
            "v3.1.1pre2",
            "v3.1.1pre1",
            "v3.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-70452.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:48.974757116Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/70xxx/CVE-2026-70452.json",
        "https://github.com/RsyncProject/rsync/releases/tag/v3.5.0",
        "https://github.com/RsyncProject/rsync/security/advisories/GHSA-6692-28cx-wpqq",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-70452",
        "https://www.vulncheck.com/advisories/rsync-access-control-bypass-via-dns-resolution-failure",
        "https://github.com/RsyncProject/rsync"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-636",
          "CWE-863"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/70xxx/CVE-2026-70452.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-70452",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 517538,
  "published_at": "2026-08-13T14:46:50.541+00:00"
}