Developer Formatter <= 2015.0.2.1 - Authenticated (Administrator+) Stored Cross-Site Scripting via Custom CSS
Strategic Overview
- Status
- Unpatched
- Affected Plugin
- Developer Formatter
- Affected Version
<= 2015.0.2.1- CVSS
- 5.5Medium
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CVE
CVE-2025-5699
At a glance
CVE-2025-5699 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Developer Formatter WordPress plugin, affecting versions <= 2015.0.2.1. It carries a CVSS score of 5.5 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Administrator level or above. No fixed release has been reported yet; treat installations running this software as exposed. Disclosed June 2025, reported by l33ch.
Vulnerability Overview
The Developer Formatter plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Custom CSS in all versions up to, and including, 2015.0.2.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level access, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user.
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Reaching this weakness in Developer Formatter <= 2015.0.2.1 takes an account at Administrator level or above. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.
Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. No fixed build of this plugin is recorded for Developer Formatter yet, so installs running <= 2015.0.2.1 stay exposed until the vendor ships one.
Remediation
No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.
How does WordSec protect against this?
An attacker needs Administrator access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. No patched version is recorded yet, which is the case where a filtering layer matters most, because there is nothing to update to.
- Firewall
- Alerts
External References
Related records
Other vulnerabilities in Developer Formatter
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