Authentication bypass by spoofing in twofactor_gauthenticator

{
  "id": "39984d7b8ffe11892dc123fc643ec9d151431c312b534a1d9b36eb57660ac693",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-107147",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Authentication bypass by spoofing in twofactor_gauthenticator",
    "summary": "The twofactor_gauthenticator plugin for Roundcube is vulnerable to 2fa authentication bypass by spoofed client address headers. Due to the lack of validation of the Client-IP and X-Forwarded-For headers, an attacker who obtains user's password can spoof a whitelisted IP address, resulting in the second factor being bypassed. This issue was fixed in commit 4640889.",
    "evidence": "cve:CVE-2026-107147",
    "products": [
      {
        "name": {
          "value": "twofactor_gauthenticator",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-107147",
      "aliases": [
        "CVE-2026-107147"
      ],
      "metrics": [
        {
          "format": "CVSS",
          "cvssV4_0": {
            "Safety": "NOT_DEFINED",
            "version": "4.0",
            "Recovery": "NOT_DEFINED",
            "baseScore": 6.3,
            "Automatable": "NOT_DEFINED",
            "attackVector": "NETWORK",
            "baseSeverity": "MEDIUM",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
            "exploitMaturity": "NOT_DEFINED",
            "providerUrgency": "NOT_DEFINED",
            "userInteraction": "NONE",
            "attackComplexity": "HIGH",
            "attackRequirements": "NONE",
            "privilegesRequired": "NONE",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "LOW",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "affected": [
        {
          "repo": "https://github.com/alexandregz/twofactor_gauthenticator",
          "vendor": "alexandregz",
          "product": "twofactor_gauthenticator",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "4640889",
              "versionType": "git"
            }
          ],
          "collectionURL": "https://github.com",
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-27T09:36:01.938Z",
      "provider": "cve",
      "references": [
        "https://cert.pl/en/posts/2026/10/CVE-2026-107145",
        "https://github.com/alexandregz/twofactor_gauthenticator/blob/master/CHANGES-2FA-SECURITY.en.md"
      ],
      "provider_metadata": {
        "cna": {
          "orgId": "4bb8329e-dd38-46c1-aafb-9bf32bcb93c6",
          "shortName": "CERT-PL",
          "dateUpdated": "2026-10-27T09:36:01.938Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-107147",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 391559,
  "published_at": "2026-10-27T09:36:01.938+00:00"
}