Nazwa wtyczki	weichuncai(WP伪春菜)
Type of Vulnerability	Zapisane XSS
CVE Number	CVE-2025-7686
Pilność	Średni
CVE Publish Date	2025-08-15
Source URL	CVE-2025-7686

WordPress weichuncai (WP伪春菜) <= 1.5 — CSRF → Stored XSS (CVE-2025-7686): What Site Owners Must Know and How to Protect Now

Autor: WP-Firewall Security Team

Data: 2025-08-16

Tagi: WordPress, Plugin Security, XSS, WAF, Incident Response, Vulnerability

Streszczenie
A recently disclosed vulnerability (CVE-2025-7686) affects the WordPress plugin “weichuncai (WP伪春菜)” versions up to and including 1.5. An unauthenticated attacker can exploit a Cross-Site Request Forgery (CSRF) to store a Cross-Site Scripting (stored XSS) payload on a target site. The vulnerability is rated with a CVSS of 7.1 (Medium) and is publicly disclosed with no official vendor patch currently available. This post explains the technical details, realistic attack scenarios, detection and logging guidance, immediate mitigations (including virtual patching via WP-Firewall), permanent fixes, and post-incident recovery steps.

Table of contents

• Background: what was disclosed
• Vulnerability overview (technical summary)
• Why CSRF chaining to stored XSS matters
• Realistic attack scenarios and impact
• How to detect if your site was exploited
• Immediate mitigation (what to do right now)
  • Enforce WordPress hardening
  • Virtual patching with WP-Firewall (recommended)
  • Temporary plugin removal or disablement
• How we create virtual patches (technical outline)
  • Example WAF rule patterns (safe, non-exploit code)
  • ModSecurity-style rule examples you can adapt
• Permanent fix recommendations for plugin developers
  • Code-level remediation (nonce checks, input validation, output escaping)
  • Example secure code snippets
• Monitoring, incident response and recovery checklist
• FAQ and additional guidance
• Try WP-Firewall free plan (Protect your site instantly)
• Wniosek

Background: what was disclosed

On 15 August 2025 a public advisory recorded CVE-2025-7686 involving the “weichuncai (WP伪春菜)” WordPress plugin in versions up to 1.5. The core issue: one or more plugin endpoints accept inputs that end up persisted and rendered back to site visitors without proper context-sensitive escaping, and those endpoints can be reached via forged requests (CSRF). Because the endpoints do not correctly verify request origin or user intent, an attacker can cause a victim site to store malicious script content. Later, when other site visitors load pages that include that stored data, the malicious JavaScript executes in their browsers.

Key facts:

• Affected plugin: weichuncai (WP伪春菜)
• Affected versions: <= 1.5
• Vulnerability types: Cross-Site Request Forgery (CSRF) chaining to Stored Cross-Site Scripting (Stored XSS)
• Privilege required to exploit: Unauthenticated (no login required)
• CVE: CVE-2025-7686
• Fix status at time of disclosure: No official fix available

Vulnerability overview (technical summary)

This issue is a two-part failure:

1. CSRF: The plugin exposes an action endpoint that performs state changes (creates or updates data) without sufficient CSRF protections. On WordPress, the standard mechanism is to require and verify a nonce (a one-time token) for any state-changing endpoint that can be accessed from a browser. If an endpoint lacks that check or the check is broken, a remote attacker can trick a logged-in user (or sometimes even a visitor, depending on how the endpoint is implemented) to submit an HTTP request to the vulnerable endpoint by luring them to an attacker-controlled page.
2. Stored XSS: The same state-changing endpoint allows attacker-controlled input into a persistent store (database, postmeta, options, etc.) and later that data is output into pages without proper escaping for the HTML/JavaScript context. When stored data is output unsafely to users’ browsers, it creates a stored XSS condition.

Why the combination is critical here: The CSRF element can be used to perform the injection without needing authenticated access (or in some cases, while relying on a minimal privilege user visiting a malicious page). The stored XSS then executes whenever an admin or any visitor loads the page containing the stored payload — potentially enabling session theft, admin account takeovers, malware distribution, redirection, or persistent site defacement.

Why CSRF chaining to stored XSS matters

Stored XSS by itself is dangerous. When combined with a CSRF vector that removes the need to trick an authenticated admin to click a specific button within the target site, the vulnerability becomes significantly more exploitable. Important points:

• Unauthenticated injection: If the vulnerable endpoint accepts unauthenticated requests, the attacker doesn’t need to trick a privileged user at all — they can inject directly.
• Broad impact: Stored XSS affects every visitor of the page rendering the malicious payload: users, editors, administrators, search engine crawlers, and more.
• Stealth and persistence: Attacks can be persistent and stealthy — payloads may not be obvious in the admin UI and can survive plugin upgrades if stored in generic database fields.
• Automation: Attackers can script mass exploitation across many sites running the vulnerable plugin.

Realistic attack scenarios and impact

Below are plausible exploitation scenarios an attacker could carry out if your site uses an affected plugin version.

1. Automated mass injection
   Attacker scans for sites running the plugin. For each site using <=1.5, the attacker sends crafted HTTP requests to the vulnerable endpoint that store script payloads. Many sites are compromised in minutes.
2. Admin account takeover through session theft
   Stored XSS can be used to exfiltrate WordPress authentication cookies or session tokens (if cookies are not properly flagged). An attacker can then use captured cookies to gain administrative access.
3. SEO spam and malicious redirects
   The attacker injects code that creates hidden spam links or redirects visitors to phishing or ad pages. This can hurt SEO, search rankings, and get the site flagged by search engines.
4. Malware distribution and drive-by downloads
   The attacker injects scripts that load external malicious payloads or start drive-by download attempts against visitors.
5. Supply-chain or lateral movement
   If an attacker gets admin access, they can pivot to add backdoors, modify other plugins or themes, or add scheduled tasks to further maintain access.

Impact depends on the site’s audience and who visits the affected pages. High-traffic sites, e-commerce stores, and membership sites face greater risk.

How to detect if your site was exploited

Detecting stored XSS injection requires a combination of log review, content scanning, and targeted database checks. Use the steps below:

1. Check web server logs and access logs
   • Look for unexpected POST/GET requests to plugin-specific endpoints around the disclosure time or earlier.
   • Note IP addresses, user agents and timestamps that look like scanner/automation patterns.
2. Search the database for suspicious payloads
   • Search wp_posts, wp_postmeta, wp_options, and plugin-specific tables for suspicious HTML or JavaScript fragments such as <script>, onerror=, javascript:, eval(, document.cookie.
   • Be mindful: attackers sometimes obfuscate code (e.g., encoded strings) — search for common patterns or base64-encoded strings.
3. Inspect front-end pages
   • View the source of pages that the plugin manages or touches. Look for injected scripts that you did not author.
4. Use malware scanners (server-side)
   • Run a server-side malware scan if available; Do not rely solely on plugin-level scanners.
5. Check admin UI
   • Some stored payloads may appear in plugin settings or UI fields. Look for unfamiliar fields or settings.
6. Monitor outgoing network connections
   • If your site is connecting to third-party IPs or domains you don’t recognize (particularly after changes), that may indicate active malicious scripts.

If you find evidence of compromise, isolate the site (maintenance mode, restrict access), take full backups of current state for forensic analysis, and follow the incident response checklist below.

Immediate mitigation — what to do right now

If you run the vulnerable plugin (weichuncai <=1.5), act immediately. We recommend the following prioritized steps:

1. Turn on maintenance mode or reduce public access (if feasible)
   • Prevent further harm to visitors by restricting public traffic temporarily.
2. Remove or disable the vulnerable plugin
   • If a plugin update is not available, disable the plugin temporarily. This is the simplest, most reliable mitigation. Note that disabling may impact site functionality — plan communications.
3. If you can’t remove the plugin right away, apply virtual patching via WP-Firewall
   • WP-Firewall can deploy a virtual patch (WAF rule) targeted at the vulnerable endpoints and payload patterns, blocking exploit attempts before they reach the application.
   • Virtual patching preserves site functionality while shielding the vulnerable code path.
4. Harden WordPress immediately
   • Ensure core, themes, and other plugins are updated.
   • Enforce strong admin credentials, remove unused admin accounts, and enable multi-factor authentication.
   • Make sure cookies use secure flags (HttpOnly, Secure, SameSite) where appropriate.
5. Scan for indicators of compromise (IOCs)
   • Perform database and file scans as described in the detection section. If you find injected payloads, clean them and consider rotating admin passwords and keys.
6. Monitor logs and set alerts
   • Enable enhanced logging of POST requests, suspicious query parameters, and unusual admin events.
7. Restore from a safe backup if necessary
   • If the infection is extensive, restoring to a backup taken before the compromise may be the fastest way to recover.

Virtual patching with WP-Firewall (recommended)

When a vendor fix is not yet available, the fastest way to protect live sites is virtual patching — using a Web Application Firewall to block exploit attempts targeted at the vulnerable code paths.

Why WP-Firewall virtual patching helps:

• Blocks malicious requests at the edge before they hit WordPress.
• Can be deployed immediately and centrally for customers on our service.
• Avoids breaking site functionality because rules can be narrowly scoped.
• Logs attempted exploit attempts for follow-up and forensics.

We provide tailored rulesets that:

• Block requests to the plugin’s known endpoints that lack valid nonces.
• Block requests containing suspicious payloads intended for stored XSS (script tags, JS event handlers, data URI scripts).
• Rate-limit and throttle suspicious behavior.
• Optionally return a benign response or 403 to blocked requests.

If you manage your own WAF, you can create temporary rules as described below.

Example WAF rule patterns (safe and practical)

Below are safe, high-level examples of what virtual patching rules look like. These are intended for administrators and WAF engineers — do not paste exploit payloads into public places.

Note: adapt regex patterns to your WAF engine and test in staging before deploying to production.

1) Block requests containing script tags in query strings or post fields (generic)

– Pattern: look for “<script” or “javascript:” or “onerror=” in parameters.
– Pseudocode:

if request.PARAMS contains /<\s*script\b/i or /javascript:/i or /\bon\w+\s*=/i { 
    block request (status 403); log incident; notify admin
}

2) Block suspicious base64 or eval usage in parameters

– Pattern: base64 strings of a certain length followed by typical decoder usage.
– Pseudocode:

if request.PARAMS matches /(?:[A-Za-z0-9+/]{40,}={0,2})/ and request.PARAMS contains /atob|fromCharCode|eval|setTimeout/ {
    block request
}

3) Protect specific plugin endpoints

– If the plugin registers a known action path such as /?action=weichuncai_save or POST to admin-ajax.php with action=weichuncai_*:

if request.URI contains "action=weichuncai" and not valid_wp_nonce(request) {
    block request
}

(If your WAF cannot validate WordPress nonces, treat requests to the endpoint as suspicious and block POST requests with dangerous payloads.)

4) Rate-limit and block automated scanning

– If you observe many requests from a single IP hitting the plugin endpoints, apply temporary IP throttling or block.

These simplified patterns help prevent common exploit techniques without adding the exact exploit payload in rules (a safer approach).

ModSecurity-style example rules (adapt to your stack)

Below are illustrative ModSecurity-style rules — adapt and test:

1) Block obvious script tags in any argument:

SecRule ARGS "(?i)<\s*script" "id:100001,phase:2,deny,status:403,log,msg:'Blocked attempt to inject script tag'"

2) Block ‘javascript:’ URI use in args:

SecRule ARGS "(?i)javascript\s*:" "id:100002,phase:2,deny,status:403,log,msg:'Blocked javascript: URI in parameter'"

3) Block POSTs to admin-ajax.php for the plugin action without nonce
(Note: evaluating WP nonces with ModSecurity may be complex; this rule blocks suspicious POSTs to the action.)

SecRule REQUEST_METHOD "POST" "chain,phase:2,id:100003,deny,status:403,log,msg:'Blocked POST to known plugin endpoint'"
    SecRule ARGS_NAMES "action" "chain"
    SecRule ARGS:action "^(?i)weichuncai_" 

Again: test rules in detection mode first (audit logging) to avoid false positives.

Permanent fix recommendations for plugin developers

If you maintain or can contact the plugin vendor, the correct steps are standard but crucial:

1. Add strong CSRF protections
   For any state-changing front-end or admin action, require and verify a WordPress nonce using wp_create_nonce() I check_admin_referer() Lub wp_verify_nonce() before processing the request.
2. Sanitize and validate input on receipt
   Use strict validation (type checks, allowed characters, max length).
   Do not accept HTML unless absolutely needed. If HTML is required, restrict to a safe subset.
3. Escape output by context
   When outputting data to HTML, use esc_html(), esc_attr(), esc_url(), wp_kses_post(), or appropriate WordPress escaping functions depending on context.
   Never echo stored data directly into page content without escaping.
4. Use capability checks and least privilege
   If an action should be available only to administrators, check current_user_can('manage_options') or an appropriate capability.
   Do not trust client-side controls.
5. Logging and auditing
   Log any failed nonce checks and suspicious activity so admins can spot attempted exploitation.
6. Provide an update and clear migration instructions
   If data needs normalization or cleanup, ship an update routine to remove suspicious stored content or escape outputs.

Example secure code snippets

Do not use these verbatim without adapting to your specific plugin architecture, but here are canonical patterns:

1) Check nonce and capability before processing:

<?php
if ( ! isset( $_POST['weichuncai_nonce'] ) || ! wp_verify_nonce( $_POST['weichuncai_nonce'], 'weichuncai_action' ) ) {
    wp_die( 'Security check failed', 'Error', array( 'response' => 403 ) );
}

if ( ! current_user_can( 'manage_options' ) ) {
    wp_die( 'Insufficient privileges', 'Error', array( 'response' => 403 ) );
}
?>

2) Sanitize user input before saving:

<?php
$raw_input = isset($_POST['weichuncai_text']) ? $_POST['weichuncai_text'] : '';
$clean_input = wp_kses( $raw_input, array(
    'a' => array( 'href' => true, 'title' => true, 'rel' => true ),
    'br' => array(),
    'em' => array(),
    'strong' => array(),
) );

update_option( 'weichuncai_text', $clean_input );
?>

3) Escape output in template:

<?php
$stored = get_option( 'weichuncai_text', '' );
// Use wp_kses_post if you allow a safe subset of HTML
echo wp_kses_post( $stored );
?>

Note: If the plugin needs to store raw HTML for legitimate reasons, ensure you limit allowed tags with wp_kses and restrict who can submit that content.

Monitoring, incident response and recovery checklist

If you suspect compromise or simply want to prepare, use this checklist:

1. Containment
   • Temporarily disable the vulnerable plugin or set site to maintenance mode.
   • Block offending IPs and enforce WAF rules.
2. Preservation
   • Take a full backup of files and database for forensic analysis.
   • Export server logs, access logs, and any application logs.
3. Eradication
   • Remove malicious scripts and clean infected files.
   • Remove suspicious database entries identified by the search patterns above.
   • Rotate all admin passwords and any API keys that may have been exposed.
4. Powrót do zdrowia
   • Restore clean backups if the infection is widespread.
   • Re-enable services and plugin after verifying cleanup and applying mitigations.
5. Post-incident actions
   • Keep a watch on logs for re-infection indicators.
   • Notify users if their data was exposed as required by policy or law.
   • Improve hardening: regular updates, scheduled scans, MFA, and principle of least privilege.
6. Report and coordinate
   • If you are a hosting provider or manage many sites, notify affected parties with remediation instructions and timelines.

FAQ and additional guidance

Q: Should I delete the plugin now?
A: If you can tolerate loss of the plugin functionality temporarily, disabling or removing it is the safest short-term option until an update is available. If you need the functionality, virtual patching via WP-Firewall is the recommended approach while waiting for a vendor patch.

Q: How long should I run the WAF rule?
A: Keep the virtual patch active until an official patched plugin version is released and you have updated every affected site. After updating, monitor logs for a few weeks before retiring the temporary rules.

Q: Are stored XSS and CSRF always combined?
A: Not always. They are distinct classes of problems, but when a request can be forged (CSRF) to a data persistence endpoint that later renders unsafely (stored XSS), they compound risk.

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Why virtual patching is a practical stopgap (and how we support you)

As maintainers of a managed WordPress WAF service, we’ve seen dozens of similar cases where virtual patching prevented widespread exploitation while developers prepared official fixes. Virtual patching works because:

• Exploitation traffic is often patternable (same parameters, similar payload signatures).
• Blocking at the HTTP layer stops exploitation before the malicious payload is persisted or rendered.
• We can fine-tune rules to minimize false positives and preserve site functionality.

Our approach is to deploy layered protections:

• Generic XSS/SQLi protection to stop common injection attempts.
• Targeted signatures for the plugin-specific endpoints involved in the disclosure, blocking the exact request shapes that lead to exploitation.
• Behavioral rules that throttle suspicious automation.

If you are an agency or host protecting many client sites, virtual patching buys you time: you can apply emergency mitigations centrally, coordinate plugin updates and cleanups, and communicate remediation status to customers.

Practical next steps for site owners (summary checklist)

1. Identify: Check if your site runs weichuncai <=1.5.
2. Contain: Disable the plugin if possible; otherwise enable WAF virtual patching.
3. Inspect: Search DB and pages for script tags or signs of stored XSS.
4. Clean: Remove malicious content, rotate credentials, and review admin users.
5. Harden: Update all components, enable MFA, and ensure cookies are secured.
6. Monitor: Watch logs and WAF alerts for continued exploit attempts.
7. Update: Apply official vendor patch when available; keep virtual patch active until then.

Closing thoughts

Stored XSS chained with CSRF is a recurring theme in WordPress plugin incidents because of two common developer oversights: failure to enforce nonces/capability checks and failure to escape output when rendering stored data. Addressing both sides — request validation and output encoding — is essential for robust defense.

If you manage one or more WordPress sites, prioritize:

• Timely patching and updates,
• Centralized protections such as a managed WAF,
• Strong authentication and monitoring.

At WP-Firewall we prioritize delivering pragmatic protections for real-world WordPress deployment patterns: fast virtual patches, clear incident guidance, and layered defenses that let you keep your site online and safe while permanent fixes are prepared.

Stay vigilant, and if your site is affected and you want assistance with virtual patching or cleanup guidance, try our free plan to start protecting immediately: https://my.wp-firewall.com/buy/wp-firewall-free-plan/

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If you want, we can prepare a one-click checklist for your site (step-by-step with exact queries to run against your database and logs) or produce a tailored virtual patch for your instance — just reply with how your site is hosted and whether you prefer managed WAF or a self-hosted rule set.