Overview
This report details a significant cybersecurity vulnerability, CVE-2025-45851, found in Hikvision’s DS-2CD1321-I V5.7.21 build 230819. The vulnerability can cause a Denial of Service (DoS) attack, which could potentially lead to system compromise or data leakage. Any organization utilizing this product version should immediately address this issue to avoid potential disruption and data loss.
Vulnerability Summary
CVE ID: CVE-2025-45851
Severity: High (7.5 CVSS Score)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Denial of Service, Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
Hikvision DS-2CD1321-I | V5.7.21 build 230819
How the Exploit Works
The exploit works by sending a specially crafted POST request to the endpoint /ISAPI/Security/challenge on a device running the vulnerable software. This malformed request causes the system to crash, resulting in a Denial of Service (DoS) condition.
Conceptual Example Code
Below is a conceptual example of how the vulnerability might be exploited. This is a sample HTTP request:
POST /ISAPI/Security/challenge HTTP/1.1
Host: target.example.com
Content-Type: application/json
{ "malicious_payload": "..." }
In this example, the “malicious_payload” is intentionally left vague. In a real-world scenario, this would contain the crafted data that triggers the vulnerability, leading to a Denial of Service.
Mitigation
The vendor, Hikvision, has released an update (V5.7.23_SP2) that fixes this vulnerability. Users are strongly advised to apply this patch immediately. Until the patch can be applied, users can use a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) as a temporary mitigation measure. However, these are not long-term solutions and do not eliminate the vulnerability.

