Cross-Site Scripting (XSS) in Simple Custom Login Page (WordPress plugin) (CVE-2026-10100)
Summary
Cross-site scripting in Simple Custom Login Page (WordPress plugin) (CVE-2026-10100). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-10100 has been found in Simple Custom Login Page (WordPress plugin).
Risk of unauthorized operations or information disclosure. CVSS score: 4.4/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Simple Custom Login Page (WordPress plugin) CVE-2026-10100" on the vendor's site.
CVE-2026-10100 (Simple Custom Login Page (WordPress plugin)) — CWE-79 / CVSS v3 4.4
Attack vector: remote (network-reachable) / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Cross-site scripting (XSS) (CWE-79) exists in Simple Custom Login Page (WordPress plugin).
Check the vendor advisory for the affected versions of Simple Custom Login Page (WordPress plugin).
Severity: Medium (CVSS 4.4/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Simple Custom Login Page (WordPress plugin) を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web nvd.nist.gov
- web security@wordfence.com
- web security@wordfence.com
- web security@wordfence.com
- web github.com