Administrator-level JavaScript execution via unescaped Site Key
Published Apr 23, 2026 · Updated Apr 23, 2026
Stored XSS in reCaptcha by WebDesignBy before 2.0 allows remote authenticated users to execute JavaScript on the WordPress login page. The grecaptcha_js() function inserts the unsanitized Site Key setting into a JavaScript string, so a closing script tag stores attacker-controlled code. Exploitation requires a multisite administrator without unfiltered_html to save the payload, after which any visitor who loads the login page executes it.
Summary
What happened
Stored XSS in reCaptcha by WebDesignBy before 2.0 allows remote authenticated users to execute JavaScript on the WordPress login page. The grecaptcha_js() function inserts the unsanitized Site Key setting into a JavaScript string, so a closing script tag stores attacker-controlled code. Exploitation requires a multisite administrator without unfiltered_html to save the payload, after which any visitor who loads the login page executes it.
The record
- CVE
- CVE-2026-4512
- Published
- Apr 23, 2026
- Updated
- Apr 23, 2026
- Vendor
- Web Design By, LLC
- Product
- reCaptcha by WebDesignBy
- Classifications
- CWE-79, T1059.007
- Attack vector
- network
- Privileges
- admin
Timeline
How it unfolded
- Apr 23, 2026CVE publishedPublication date reported by the CVE source.
- Apr 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <2.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- WPScan stored-XSS proof of conceptproof of concept · validated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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