CVE-2025-56266

CriticalPublic PoC

Published: 08 September 2025

Published

08 September 2025

Modified

12 September 2025

KEV Added

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Patch

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CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0713 91.6th percentile

Risk Priority 24 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-56266 is a critical-severity Injection (CWE-74) vulnerability in Avigilon Access Control Manager. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 8.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190). What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-10 Information Input Validation good match

prevent

SI-10 mandates information input validation at entry points, directly preventing host header injection by rejecting or sanitizing crafted Host headers used to execute arbitrary code.

SI-2 Flaw Remediation good match

prevent

SI-2 requires timely flaw remediation including patching known vulnerabilities like CVE-2025-56266 to eliminate the host header injection weakness.

SC-7 Boundary Protection partial match

prevent

SC-7 boundary protection via web application firewalls or proxies can inspect and block malformed HTTP requests exploiting host header injection.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

Why these techniques?

Host Header Injection vulnerability in Avigilon ACM enables remote arbitrary code execution via crafted URL, facilitating exploitation of public-facing applications.

NVD Description

A Host Header Injection vulnerability in Avigilon ACM v7.10.0.20 allows attackers to execute arbitrary code via supplying a crafted URL.

Deeper analysisAI

CVE-2025-56266 is a Host Header Injection vulnerability in Avigilon ACM version 7.10.0.20. The flaw enables attackers to execute arbitrary code by supplying a crafted URL. It is linked to CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')), CWE-116 (Improper Encoding or Escaping of Output), and CWE-444 (Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')).

The vulnerability carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), marking it as critical. Remote attackers require only network access, with low attack complexity, no privileges or user interaction needed. Successful exploitation allows high-impact compromise of confidentiality, integrity, and availability on the target system through arbitrary code execution.

Researcher-provided details, including exploitation paths, are documented in GitHub repositories at https://github.com/nikolas-ch/CVEs/blob/main/AvigilonACM_v7.10.0.20/HostHeaderInjection/HostHeaderInjection.txt, https://github.com/nikolas-ch/CVEs/tree/main/AvigilonACM_v7.10.0.20/, and https://github.com/nikolas-ch/CVEs/tree/main/AvigilonACM_v7.10.0.20/HostHeaderInjection. No official advisories or patches are referenced in the CVE publication dated 2025-09-08.