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CVE-2026-16639

Status: Awaiting AnalysisCritical (9.8)—

Authentication Bypass Using an Alternate Path or Channel vulnerability in Drupal Internationalization Single Sign-On allows Authentication Bypass. This issue affects Internationalization Single Sign-On versions: from 0.0.0 to 1.8.0.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Vector CVSS:3.1/AV:N/AC:L/PR:N permite ejecución sin autenticación; CWE-288 (autenticación débil) y descripción de bypass autenticar sin credenciales válidas, ganando acceso a cuentas (T1078).

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Privileged Account ManagementApplication Developer GuidanceActive Directory ConfigurationVulnerability ScanningUser TrainingUser Account Management

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Drupal — Internationalization Single Sign ONAI

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-16639",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-16639",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-08-26T15:22:48.162413Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "mlhess@drupal.org",
      "affectedData": [
        {
          "repo": "https://git.drupalcode.org/project/i18n_sso",
          "vendor": "Drupal",
          "product": "Internationalization Single Sign-On",
          "versions": [
            {
              "status": "affected",
              "version": "0.0.0",
              "lessThan": "1.8.0",
              "versionType": "semver"
            }
          ],
          "collectionURL": "https://www.drupal.org/project/i18n_sso"
        }
      ]
    }
  ],
  "published": "2026-08-25T23:16:56.673",
  "references": [
    {
      "url": "https://www.drupal.org/sa-contrib-2026-081",
      "source": "mlhess@drupal.org"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "mlhess@drupal.org",
      "description": [
        {
          "lang": "en",
          "value": "CWE-288"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Authentication Bypass Using an Alternate Path or Channel vulnerability in Drupal Internationalization Single Sign-On allows Authentication Bypass. This issue affects Internationalization Single Sign-On versions: from 0.0.0 to 1.8.0."
    }
  ],
  "lastModified": "2026-08-28T15:29:44.967",
  "sourceIdentifier": "mlhess@drupal.org"
}