Skip to main content
Live Webinar with SANS (June 25)— Agentic CTI Automation for Fun & ProfitRegister Free
Mallory
High

CSRF to RCE in WordPress Theme Editor plugin

IdentifiersCVE-2025-9890CWE-352· Cross-Site Request Forgery (CSRF)

CVE-2025-9890 affects the Theme Editor plugin for WordPress in all versions up to and including 3.0. The vulnerability is a Cross-Site Request Forgery issue caused by missing or incorrect nonce validation on the 'theme_editor_theme' page. Because the affected action does not properly verify request authenticity, an attacker can induce a privileged WordPress administrator to submit a forged request. In the context of a theme editor component, successful exploitation can result in unauthorized modification of theme files, leading to remote code execution on the WordPress server.

Share:
For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an unauthenticated attacker to leverage an administrator's authenticated session to perform unauthorized actions in the Theme Editor plugin. The stated impact is remote code execution, which can enable arbitrary PHP code injection or modification of theme files, resulting in full compromise of the WordPress application context. Depending on server configuration, this may permit website defacement, malware deployment, persistence, credential theft, and further pivoting from the compromised host.

Mitigation

If you can’t patch tonight, do this now.

Restrict administrator exposure to untrusted links and web content until the plugin is patched. Disable the Theme Editor plugin or any file-editing functionality it exposes if not strictly required. Apply least-privilege administration practices, use separate low-privilege accounts for routine browsing, and consider additional hardening such as WAF rules or administrative access restrictions to reduce the likelihood of successful CSRF delivery. Logging and file integrity monitoring for theme file changes can help detect exploitation.

Remediation

Patch, then assume compromise.

Update the Theme Editor plugin to a version newer than 3.0 if a vendor fix is available. If no patched release is yet available, disable or remove the plugin until a fix is published. The underlying issue should be remediated by implementing proper nonce validation and capability checks on requests to the 'theme_editor_theme' page, ensuring state-changing actions cannot be performed via forged cross-site requests.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2

Community discussion across Reddit, Mastodon, and other social sources.