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CVE-2026-6203 - Membership Plugin

CVE-2026-6203

The User Registration & Membership plugin for WordPress is vulnerable to Open Redirect in versions up to and including 5.1.4. This is due to insufficient validation of user-supplied URLs passed via the 'redirect_to_on_logout' GET parameter before redirecting users. The `redirect_to_on_logout` GET parameter is passed directly to WordPress's `wp_redirect()` function instead of the domain-restricted `wp_safe_redirect()`. While `esc_url_raw()` is applied to sanitize malformed URLs, it does not restrict the redirect destination to the local domain, allowing an attacker to craft a specially formed link that redirects users to potentially malicious external URLs after logout, which could be used to facilitate phishing attacks.

CVE-2026-6203

MEDIUM CVSS 6.1 Published 2026-04-13 Updated 2026-04-13
AI Risk Elevated (61/100) Active Exploit: No strong signal Published Exploit: No public exploit references Priority: P3 Priority
Severity Band MEDIUM
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Affected Components 2
Reference Links 3
AI Risk Engine Elevated (61/100)
Exploitability High
Active Exploitation No strong signal
Published Exploit Status No public exploit references

Threat Timeline

  1. 2026-04-13 CVE published and first recorded in the threat feed.
  2. 2026-04-13 Record updated with latest vulnerability metadata.
  3. 2026-04-15 AI technical context refreshed for mitigation and impact guidance.
  4. Now Monitoring for follow-up changes, linked references, and new related CVEs.

AI Context

Machine-generated threat intelligence

AI Updated 20 hours ago

AI enriched 20 hours ago (2026-04-15 00:11 UTC)

Technical Summary

The User Registration & Membership plugin for WordPress is vulnerable to Open Redirect in versions up to and including 5.1.4. This is due to insufficient validation of user-supplied URLs passed via the 'redirect_to_on_logout' GET parameter before redirecting users. The `redirect_to_on_logout` GET parameter is passed directly to WordPress's `wp_redirect()` function instead of the domain-restricted `wp_safe_redirect()`. While `esc_url_raw()` is applied to sanitize malformed URLs, it does not restrict the redirect destination to the local domain, allowing an attacker to craft a specially…

Potential Impact

Severity is MEDIUM (CVSS 6.1). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.

Exploitability Assessment

Exploitability is assessed as High based on remote code execution potential.

Primary risk drivers: remote code execution potential

Mitigation Recommendations

Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.

Detection & Monitoring

Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.

Business Impact Lens

AI risk score 61/100 (Elevated, High) with priority P3 Priority. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.

Affected Products

Membership PLUGIN · membership Affected: <= 5.1.4 Fixed version not specified
User Registration PLUGIN · user-registration Affected: <= 5.1.4 Fixed version not specified
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