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CVE-2026-18386

Status: DeferredMedium (4.9)—

The WP BackItUp Community Edition plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 2.1.0 via the 'backup_file' parameter parameter. This makes it possible for authenticated attackers, with administrator-level access and above, to read the contents of arbitrary files on the server, which can contain sensitive information. The basename() normalization present in the handler only executes when the traversed target path does not exist, providing no protection against reads of existing files.

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).

Affected technologies (1)

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

Wpbackitup — WP BackitupAI

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-18386",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-18386",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-09-10T20:37:00.758828Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security@wordfence.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 4.9,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "HIGH",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.2
      }
    ]
  },
  "affected": [
    {
      "source": "security@wordfence.com",
      "affectedData": [
        {
          "vendor": "cssimmon",
          "product": "WP BackItUp Community Edition",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "versionType": "semver",
              "lessThanOrEqual": "2.1.0"
            }
          ],
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-09-10T04:17:48.437",
  "references": [
    {
      "url": "https://plugins.trac.wordpress.org/browser/wp-backitup/tags/2.0.0/lib/includes/class-wpbackitup-admin.php#L1391",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/wp-backitup/tags/2.0.0/lib/includes/handler_download.php#L30",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/wp-backitup/tags/2.0.0/lib/includes/handler_download.php#L73",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/wp-backitup/tags/2.0.0/lib/includes/handler_download.php#L77",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/wp-backitup/tags/2.1.0/lib/includes/class-wpbackitup-admin.php#L1391",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/wp-backitup/tags/2.1.0/lib/includes/handler_download.php#L30",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/wp-backitup/tags/2.1.0/lib/includes/handler_download.php#L73",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://plugins.trac.wordpress.org/browser/wp-backitup/tags/2.1.0/lib/includes/handler_download.php#L77",
      "source": "security@wordfence.com"
    },
    {
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/50272c8a-2e23-490d-8865-68ae49228895?source=cve",
      "source": "security@wordfence.com"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security@wordfence.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "The WP BackItUp Community Edition plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 2.1.0 via the 'backup_file' parameter parameter. This makes it possible for authenticated attackers, with administrator-level access and above, to read the contents of arbitrary files on the server, which can contain sensitive information. The basename() normalization present in the handler only executes when the traversed target path does not exist, providing no protection against reads of existing files."
    }
  ],
  "lastModified": "2026-09-10T21:17:23.503",
  "sourceIdentifier": "security@wordfence.com"
}