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How the CVE Works:
CVE-2025-3691 is an SSRF vulnerability in Seven Bears Library CMS 2023’s Add Link Handler component. Attackers manipulate input fields to force the server into making unauthorized internal/external HTTP requests. This occurs due to insufficient validation of user-supplied URLs, allowing crafted requests to bypass security checks. The vulnerability is remotely exploitable with low attack complexity but requires high privileges (PR:H). Successful exploitation can lead to internal network reconnaissance, data leakage, or chained attacks against backend systems.
DailyCVE Form:
Platform: Seven Bears CMS
Version: 2023
Vulnerability: SSRF
Severity: Medium
Date: 04/24/2025
What Undercode Say:
Analytics:
- Attack Vector: Network (AV:N)
- Privilege Required: High (PR:H)
- Exploitability: Remote, Low Complexity
Exploit Commands:
curl -X POST "http://target/cms/add_link.php" -d "url=http://internal-service/admin"
import requests
payload = {"url": "file:///etc/passwd"}
requests.post("http://target/cms/add_link.php", data=payload)
Mitigation:
1. Patch: Apply vendor updates.
2. Input Validation:
if (!filter_var($_POST['url'], FILTER_VALIDATE_URL, FILTER_FLAG_HOST_REQUIRED)) {
die("Invalid URL");
}
3. Network Controls:
iptables -A OUTPUT -d 192.168.0.0/16 -j DROP
4. WAF Rules:
location /cms/add_link.php {
deny all;
}
Detection:
grep -r "file_get_contents(" /var/www/cms/
SELECT FROM cms_logs WHERE request LIKE "%add_link.php%url=%";
Impact Reduction:
- Disable PHP wrappers (
allow_url_fopen=Off). - Restrict server outbound traffic.
- Audit user roles (PR:H requirement).
References:
- VulDB Entry: VulDB-3691
- NVD: CVE-2025-3691
No additional commentary.
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
