Urgent: CVE-2025-48320 — BaiduShare WP plugin (≤ 1.0.6) — CSRF leading to Stored XSS

Published: August 2025   |   CVE: CVE-2025-48320   |   Affected software: 百度分享按钮 (Baidu Share Button) WordPress plugin — versions ≤ 1.0.6   |   Severity (reported): CVSS 7.1 (High)   |   Status: No official vendor fix available at time of publication.

As a Hong Kong–based security practitioner with hands‑on experience defending WordPress sites, I present a focused, practical analysis of CVE‑2025‑48320. This advisory explains the technical chain (CSRF → stored XSS), likely attacker scenarios, immediate detection and remediation steps, and longer‑term hardening measures. I will not publish exploit code or step‑by‑step attack instructions — the goal is clear defensive action and forensic guidance.

Executive summary

• The BaiduShare WP plugin contains a request‑verification weakness that can be abused via CSRF to store attacker‑controlled HTML/JavaScript in the site (stored XSS).
• An attacker who gets a privileged user to load crafted content can cause persistent JavaScript to be saved in plugin settings or other stored fields; that script executes later in the context of the site.
• Impact includes session theft, data exfiltration, account takeover and site compromise. Although exploitation often needs social engineering, the persistence of stored XSS raises risk significantly.
• At time of writing there is no official patch. Treat installations with version ≤ 1.0.6 as high‑risk and act immediately.

What is CSRF → Stored XSS? How the chain works

The chain combines two weaknesses:

1. CSRF (Cross‑Site Request Forgery) — forcing an authenticated user’s browser to perform actions (for example, via a hidden form or crafted image) that the site trusts because the browser sends session cookies.
2. Stored XSS (Persistent Cross‑Site Scripting) — attacker HTML/JS is saved in the database and later rendered without proper escaping, causing script execution in other users’ browsers.

For CVE‑2025‑48320, a CSRF request can cause the plugin to persist attacker content into options/postmeta/widget fields. When those fields are rendered in admin screens or public pages, the script runs with the site origin and can abuse session tokens, REST APIs, or perform privileged actions.

Who is at risk?

• Any WordPress site with the BaiduShare plugin installed at version ≤ 1.0.6.
• Sites where admins, editors, or other high‑privilege users can log into wp‑admin and access plugin settings or pages the plugin renders.
• Sites without edge controls (WAF/host controls) or without rigorous sanitization on plugin output.

Typical attacker scenarios

1. Social engineering against an administrator
   Attacker lures an admin to a controlled page that silently issues a POST to a vulnerable plugin endpoint, storing an XSS payload in plugin settings. Later rendering executes the payload.
2. Unauthenticated trigger (if permissions are missing)
   If the plugin endpoint lacks capability checks, attackers may POST directly without social engineering, increasing scale of impact.
3. Supply chain or cross‑plugin abuse
   Data written by other plugins or third‑party integrations might be rendered later by BaiduShare without sanitization, enabling indirect injection.

Detection: what to look for now

If you manage affected sites, prioritise these checks:

• Plugin version: Confirm via WP Admin → Plugins or by inspecting wp-content/plugins/…; if ≤ 1.0.6 treat as vulnerable.
• Server logs: Look for suspicious POSTs to plugin endpoints, unusual parameters, or requests missing nonces/referrers that nonetheless succeeded.
• Database searches: Scan wp_options, wp_postmeta and plugin tables for <script, onerror=, onload=, javascript: or long encoded payloads.
• Admin activity: New admin users, unexpected setting changes, or modified posts by unknown actors.
• Browser inspection: Visit admin pages with developer tools open — watch for inline script execution or unexpected console messages.

If you find injected scripts or unauthorized changes, assume compromise and follow incident response steps below.

Immediate remediation checklist (priority order)

Actions to take immediately if you run an affected site and cannot remove the plugin right away:

1. Isolate and deactivate: Deactivate the BaiduShare plugin from wp-admin if possible. If admin access is unsafe, rename the plugin folder via SFTP/SSH (e.g. wp-content/plugins/baidushare-wp → baidushare-wp_disabled) to stop code execution.
2. Block plugin endpoints at the edge: If you have a WAF or hosting firewall, add temporary rules to block POST/GET requests to the plugin’s admin/action endpoints or known action parameters. If you lack such controls, ask your host to apply temporary blocking rules.
3. Rotate credentials and invalidate sessions: Force password resets for all administrative accounts, invalidate active sessions (change salts or use session‑management plugins), and rotate API keys used by the site.
4. Scan and clean stored payloads: Search the database for suspicious HTML/JS and remove or sanitize entries, prioritising plugin-related option keys, post content and widgets. Keep backups before destructive changes.
5. Audit accounts and scheduled tasks: Remove unknown admin users, reduce privileges where possible, and inspect/scrub suspicious cron jobs or scheduled tasks.
6. Backup and preserve evidence: Export logs and database snapshots for forensic analysis before cleanup to preserve timelines and indicators of compromise.
7. Hardening: Enable two‑factor authentication, limit admin accounts, disable file editors (define(‘DISALLOW_FILE_EDIT’, true);), and add a Content Security Policy to reduce the risk of injected script execution.
8. Replace the plugin: Do not reactivate the affected plugin until a vendor patch is available and validated. If the plugin appears abandoned, replace it with a maintained alternative and migrate settings carefully, avoiding copying potentially tainted content.

Database forensics — safe searching for injected content

When searching the DB, avoid destructive queries. Example safe steps:

• Search for suspect strings: <script, onerror=, onload=, javascript: in wp_options.option_value, wp_posts.post_content, and wp_postmeta.meta_value.
• Check timestamps and recently modified rows to prioritise likely injection windows.
• Export suspicious rows to a secure location for analysis before modifying.
• When removing entries, prefer sanitising or replacing values rather than blind deletion to avoid breaking site configuration.

Longer‑term remediation and hardening

• Maintain regular, versioned backups and test restore procedures.
• Keep an inventory of installed plugins and remove unmaintained components.
• Apply principle of least privilege for user roles and APis.
• Monitor logs and set alerts for unusual POSTs, new admin accounts or sudden file changes.
• Implement security headers (CSP, HSTS) and secure cookie attributes (HttpOnly, Secure, SameSite).

Virtual patching and WAF guidance (practical, vendor‑neutral)

While waiting for a vendor patch or while planning plugin replacement, virtual patching via a capable WAF or edge filter is an effective stopgap. Practical, non‑vendor recommendations:

• Block or restrict plugin admin endpoints: Deny external POST requests to plugin action URLs from outside the admin context; allow only requests with valid referer/origin headers from your site or known admin IPs.
• Enforce referrer/origin checks: Blocking requests lacking reasonable Origin/Referer headers reduces CSRF risk for modern browsers (not a perfect control but useful).
• Validate Content‑Type and request structure: Block requests with unexpected content types or payloads that contain script signatures (encoded payloads, <script, event attributes).
• Response hardening: Where possible, strip or neutralise inline <script> tags from plugin settings pages at the edge, or inject CSP rules that disallow unsafe inline scripts to reduce execution risk.
• Behavioral detection: Flag patterns such as POST to a plugin endpoint followed by rendering of stored content containing script tags; quarantine or block rendering until content is inspected.

Why virtual patching matters in practice

Maintainers sometimes delay fixes or projects become unmaintained. Virtual patching provides a practical defence-in-depth control:

• Stops the initial storing of malicious content by blocking CSRF‑style requests.
• Can prevent stored payloads from executing by modifying responses or applying CSP rules.
• Buys time for forensic cleanup and safe migration away from vulnerable components.

Recovery checklist after confirmed compromise

1. Contain: deactivate the vulnerable plugin and block identified malicious IPs or request patterns.
2. Eradicate: remove stored payloads from the database and restore clean files from trusted backups.
3. Recover: rotate credentials, enable 2FA, verify and harden admin accounts, and reissue API tokens.
4. Rebuild if necessary: if file backdoors exist, rebuild the site from clean sources and reinstall plugins/themes from official repositories.
5. Monitor: increase logging and monitoring to detect recurrence.
6. Report: notify stakeholders and comply with any disclosure or legal reporting obligations.

Practical examples of safe checks (non‑destructive)

• Use read‑only DB queries to find suspect strings. Example (WP‑CLI read only):

  wp db query "SELECT option_name, option_value FROM wp_options WHERE option_value LIKE '%<script%';"

• Export suspicious rows for offline analysis before editing.
• Test cleanup steps on a staging copy before applying them to production.

Should you remove the plugin or keep it deactivated?

Removing the plugin is the safest option when no vendor patch exists. Deactivation stops plugin code execution, but persistent malicious content in the DB can still present risk if other code renders it. When replacing, migrate settings carefully and avoid importing tainted values.

Communication with users and stakeholders

If compromise is suspected, provide clear, concise communications:

• Summarise what happened without publishing exploit details.
• Indicate what data may be affected and what steps you have taken (deactivation, cleanup, password resets).
• Advise users on actions (change password, reauthenticate, enable 2FA).
• Provide a contact for follow‑up and status updates.

Final recommendations — practical priority list

1. If you have the vulnerable plugin installed (≤ 1.0.6): deactivate and remove it immediately if it is safe to do so.
2. If you cannot remove it immediately: deploy edge rules or a WAF that blocks the plugin’s endpoints and strips risky payloads.
3. Scan and clean the database for stored scripts in options, postmeta, posts and widgets.
4. Rotate admin passwords and API keys, invalidate sessions and enable 2FA.
5. Replace the plugin with a maintained alternative and minimise plugin bloat.
6. Maintain frequent backups, monitor logs and set alerts for suspicious admin activity.

Closing note from a Hong Kong security practitioner

CSRF → stored XSS chains are attractive to attackers because a single crafted request can deliver a durable foothold. In my work across Hong Kong and the region I have seen small validation omissions escalate into major incidents. Apply a layered defence: remove immediate vulnerabilities, apply virtual patches at the edge, and harden accounts and site configuration. If you need incident response assistance, work with experienced responders who will prioritise containment, forensics and safe recovery.

Stay vigilant and prioritise removal or replacement of any unpatched component.