CVE-2026-4021
Contest Gallery <= 28.1.5 - Unauthenticated Privilege Escalation Admin Account Takeover via Registration Confirmation Email-to-ID Type Confusion
- Published
- Updated
- Reserved
- Assigned by
- Wordfence
Description
The Contest Gallery plugin for WordPress is vulnerable to an authentication bypass leading to admin account takeover in all versions up to, and including, 28.1.5. This is due to the email confirmation handler in `users-registry-check-after-email-or-pin-confirmation.php` using the user's email string in a `WHERE ID = %s` clause instead of the numeric user ID, combined with an unauthenticated key-based login endpoint in `ajax-functions-frontend.php`. When the non-default `RegMailOptional=1` setting is enabled, an attacker can register with a crafted email starting with the target user ID (e.g., `[email protected]`), trigger the confirmation flow to overwrite the admin's `user_activation_key` via MySQL integer coercion, and then use the `post_cg1l_login_user_by_key` AJAX action to authenticate as the admin without any credentials. This makes it possible for unauthenticated attackers to take over any WordPress administrator account and gain full site control.
Timeline
ID reserved
By Wordfence
- 12 days later
· 12 days later
Published
- 16 days later
· 16 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| WordfenceCNA (assigner) | 3.1 | High8.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Deferred | 3.1 | High8.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.45% · top 60% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.1.
Weakness
Affected products
References (6)
- https://www.wordfence.com/threat-intel/vulnerabilities/id/f1b9725b-dee5-44ca-bb33-c6812fb76adc?source=cve (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/contest-gallery/trunk/v10/v10-admin/users/frontend/registry/users-registry-check-after-email-or-pin-confirmation.php#L153 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/contest-gallery/tags/28.1.4/v10/v10-admin/users/frontend/registry/users-registry-check-after-email-or-pin-confirmation.php#L153 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/contest-gallery/trunk/ajax/ajax-functions-frontend.php#L204 (opens in a new tab)
- https://plugins.trac.wordpress.org/browser/contest-gallery/tags/28.1.4/ajax/ajax-functions-frontend.php#L204 (opens in a new tab)
- https://plugins.trac.wordpress.org/changeset?old_path=/contest-gallery/tags/28.1.5&new_path=/contest-gallery/tags/28.1.6 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-4021)Record last updated .