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FKIE_CVE-2026-83628

Vulnerability from fkie_nvd - Published: 2026-09-05 06:17 - Updated: 2026-09-08 13:12
Severity
4.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Summary
The Theme My Login plugin for WordPress is vulnerable to Missing Authorization in versions up to, and including, 7.1.15 on Multisite installations. This is due to the `tml_ms_signup_handler()` function's `gimmeanotherblog` branch failing to enforce the network's `active_signup` registration policy, checking only `is_user_logged_in()` while sibling branches such as `validate-blog-signup` apply the full policy gate. This makes it possible for authenticated attackers, with Subscriber-level access and above, to directly POST `stage=gimmeanotherblog` to Theme My Login's signup route, bypassing the configured registration policy entirely — even when it is set to `none` or `user` — which causes `wpmu_create_blog()` to execute with the attacker's user ID, after which WordPress core assigns the Administrator role on the newly created subsite via `add_user_to_blog()`. The privilege gain is scoped to the newly created subsite only; the attacker's account retains Subscriber-level access on the main site and does not obtain Super Admin or network-level capabilities such as `manage_network` or `manage_sites`.
References
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L580
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L661
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L708
security@wordfence.comhttps://plugins.trac.wordpress.org/changeset/3669721/theme-my-login/trunk/includes/ms-functions.php
security@wordfence.comhttps://plugins.trac.wordpress.org/changeset?old_path=%2Ftheme-my-login/tags/7.1.15&new_path=%2Ftheme-my-login/tags/7.2.0
security@wordfence.comhttps://plugins.trac.wordpress.org/changeset?reponame=&new=3669722%40theme-my-login%2Ftags%2F7.2.0&old=3643898%40theme-my-login%2Ftags%2F7.1.15
security@wordfence.comhttps://www.wordfence.com/threat-intel/vulnerabilities/id/72585c12-baa9-4c63-8584-906a1d3b332f?source=cve
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Theme My Login",
          "vendor": "jfarthing84",
          "versions": [
            {
              "lessThanOrEqual": "7.1.15",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "security@wordfence.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The Theme My Login plugin for WordPress is vulnerable to Missing Authorization in versions up to, and including, 7.1.15 on Multisite installations. This is due to the `tml_ms_signup_handler()` function\u0027s `gimmeanotherblog` branch failing to enforce the network\u0027s `active_signup` registration policy, checking only `is_user_logged_in()` while sibling branches such as `validate-blog-signup` apply the full policy gate. This makes it possible for authenticated attackers, with Subscriber-level access and above, to directly POST `stage=gimmeanotherblog` to Theme My Login\u0027s signup route, bypassing the configured registration policy entirely \u2014 even when it is set to `none` or `user` \u2014 which causes `wpmu_create_blog()` to execute with the attacker\u0027s user ID, after which WordPress core assigns the Administrator role on the newly created subsite via `add_user_to_blog()`. The privilege gain is scoped to the newly created subsite only; the attacker\u0027s account retains Subscriber-level access on the main site and does not obtain Super Admin or network-level capabilities such as `manage_network` or `manage_sites`."
    }
  ],
  "id": "CVE-2026-83628",
  "lastModified": "2026-09-08T13:12:58.310",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 4.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 1.4,
        "source": "security@wordfence.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-83628",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-07T11:08:28.886813Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-05T06:17:10.230",
  "references": [
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L580"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L661"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L708"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/changeset/3669721/theme-my-login/trunk/includes/ms-functions.php"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/changeset?old_path=%2Ftheme-my-login/tags/7.1.15\u0026new_path=%2Ftheme-my-login/tags/7.2.0"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/changeset?reponame=\u0026new=3669722%40theme-my-login%2Ftags%2F7.2.0\u0026old=3643898%40theme-my-login%2Ftags%2F7.1.15"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/72585c12-baa9-4c63-8584-906a1d3b332f?source=cve"
    }
  ],
  "sourceIdentifier": "security@wordfence.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-862"
        }
      ],
      "source": "security@wordfence.com",
      "type": "Secondary"
    }
  ]
}



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