CVE-2026-10100 - Simple Custom Login Page Plugin
CVE-2026-10100
The Simple Custom Login Page plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the color settings fields (Page Background, Form Background, Text Color, Link Color) in versions up to and including 1.0.3. This is due to insufficient input sanitization of the color option values (they were registered with register_setting() and stored via the Settings API/update_option() with no sanitize_callback) combined with the values being output into a block on wp-login.php using esc_attr(), which is incorrect for a CSS context (it does not escape ;, {, }, / or *). This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary CSS rules into the login page that are rendered for all unauthenticated visitors, enabling UI-redress and credential-phishing attacks.
CVE-2026-10100
MEDIUM
CVSS 4.4
Published 2026-06-02
Updated 2026-06-17
AI Risk Moderate (53/100)
Active Exploit: No strong signal
Published Exploit: No public exploit references
Priority: P4 Planned
Severity Band
MEDIUM
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N
Affected Components
1
Reference Links
3
AI Risk Engine
Moderate (53/100)
Exploitability
High
Active Exploitation
No strong signal
Published Exploit Status
No public exploit references
AI Context
Machine-generated threat intelligence
AI
Updated 17 days ago
AI enriched 17 days ago (2026-06-06 06:22 UTC)
Technical Summary
The Simple Custom Login Page plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the color settings fields (Page Background, Form Background, Text Color, Link Color) in versions up to and including 1.0.3. This is due to insufficient input sanitization of the color option values (they were registered with register_setting() and stored via the Settings API/update_option() with no sanitize_callback) combined with the values being output into a block on wp-login.php using esc_attr(), which is incorrect for a CSS context…
Potential Impact
Severity is MEDIUM (CVSS 4.4). 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, low-bar exploit prerequisites.
Primary risk drivers: remote code execution potential, low-bar exploit prerequisites
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 53/100 (Moderate, High) with priority P4 Planned. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.
