Grav Login OAuth Plugin before 1.4.3 Predictable Local Credentials Authentication Bypass

{
  "id": "d11527b891f316341a58cf0f165e89deca5a8a7b3fe3fc7d3de453d7725919f6",
  "url": "https://osv.dev/vulnerability/CVE-2026-109321",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Grav Login OAuth Plugin before 1.4.3 Predictable Local Credentials Authentication Bypass",
    "summary": "Grav Login OAuth plugin (grav-plugin-login-oauth) before 1.4.3 provisions OAuth accounts as ordinary Grav users with a deterministic . username and an unsalted MD5 hash of the provider identifier as the password, without disabling password login. Unauthenticated remote attackers who learn or guess a provider identifier can reproduce these credentials and log in, gaining administrative control of privileged accounts.",
    "evidence": "osv:CVE-2026-109321",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-109321",
      "aliases": [
        "CVE-2026-109321",
        "GHSA-mj8v-hvf6-73gm"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/getgrav/grav",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "c64590af161cd3874027ab3c72912d3a5fb31e06"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.4.3"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            },
            {
              "repo": "https://github.com/getgrav/grav-plugin-login-oauth",
              "type": "GIT",
              "events": [
                {
                  "introduced": "db4d1e973bc2c9ecad045d88353a45722aca621e"
                },
                {
                  "fixed": "7d642ca6bd8edc375422b704d3d30163df536ab0"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "1.0.0-beta.1"
                      },
                      {
                        "fixed": "1.4.3"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.4.2",
            "1.4.1",
            "1.4.0",
            "1.3.10",
            "1.3.9",
            "1.3.8",
            "1.3.7",
            "1.3.6",
            "1.3.5",
            "1.3.4",
            "1.3.3",
            "1.3.2",
            "1.3.1",
            "1.3.0",
            "1.2.4",
            "1.2.3",
            "1.2.2",
            "1.2.1",
            "1.2.0",
            "1.1.17",
            "1.1.9-rc.3",
            "1.1.9-rc.2",
            "1.1.9-rc.1",
            "1.1.0-rc.3",
            "1.1.0-rc.2",
            "1.1.0-rc.1",
            "1.1.0-beta.5",
            "1.1.0-beta.4",
            "1.1.0-beta.3",
            "1.1.0-beta.2",
            "1.1.0-beta.1",
            "0.9.19",
            "0.9.18",
            "0.9.17",
            "0.9.16",
            "0.9.15",
            "0.9.14",
            "0.9.13",
            "0.9.12",
            "0.9.11",
            "0.9.10",
            "0.9.9",
            "0.9.8",
            "0.9.7",
            "0.9.6",
            "0.9.5",
            "0.9.4",
            "0.9.3",
            "0.9.2",
            "0.9.0",
            "0.8.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-109321.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.295113469Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109321.json",
        "https://github.com/getgrav/grav/security/advisories/GHSA-mj8v-hvf6-73gm",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-109321",
        "https://www.vulncheck.com/advisories/grav-login-oauth-plugin-before-1.4.3-predictable-local-credentials-authentication-bypass",
        "https://github.com/getgrav/grav-plugin-login-oauth"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1391"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109321.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-109321",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 492076,
  "published_at": "2026-10-12T16:05:13.414+00:00"
}