Contest Gallery <= 28.1.5 - Unauthenticated Privilege Escalation Admin Account Takeover via Registration Confirmation Email-to-ID Type Confusion
Summary
| CVE | CVE-2026-4021 |
|---|---|
| State | PUBLISHED |
| Assigner | Wordfence |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-24 00:16:31 UTC |
| Updated | 2026-04-24 16:32:53 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 8.1 HIGH from [email protected]
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.002700000 probability, percentile 0.505020000 (date 2026-04-26)
Problem Types: CWE-287 | CWE-287 CWE-287 Improper Authentication
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 8.1 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 8.1 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Contest-gallery | Contest Gallery Upload Vote Photos Media Sell With PayPal Stripe | affected 28.1.5 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.wordfence.com/threat-intel/vulnerabilities/id/f1b9725b-dee5-44ca-bb33-c6812... | [email protected] | www.wordfence.com | |
| plugins.trac.wordpress.org/changeset | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/contest-gallery/trunk/ajax/ajax-functions-frontend.php | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/contest-gallery/trunk/v10/v10-admin/users/frontend/re... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/contest-gallery/tags/28.1.4/ajax/ajax-functions-front... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/contest-gallery/tags/28.1.4/v10/v10-admin/users/front... | [email protected] | plugins.trac.wordpress.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Supakiad S. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-03-11T20:26:17.000Z | Vendor Notified |
| CNA | 2026-03-23T11:19:11.000Z | Disclosed |
There are currently no legacy QID mappings associated with this CVE.