CVE-2022-39291 is a vulnerability in ZoneMinder, an open-source closed-circuit television (CCTV) software application widely used for video surveillance management. The flaw arises from improper input validation (CWE-20) in the handling of log data submitted via HTTP POST requests to the "/zm/index.php" endpoint. Specifically, users with "View" system permissions, which are typically read-only, can inject arbitrary data into the ZoneMinder logs. This injection is not rate-limited, allowing an attacker to repeatedly submit crafted log entries. The consequence of this unchecked input and lack of rate control is twofold: it can degrade database performance due to excessive or malformed log entries and potentially exhaust storage resources by filling log storage with injected data. This can lead to denial of service conditions affecting the availability of the ZoneMinder system. The vulnerability affects ZoneMinder versions prior to 1.36.27 and versions from 1.37.0 up to but not including 1.37.24. No known exploits have been reported in the wild, and no effective workarounds exist other than upgrading to patched versions. The vulnerability does not require elevated privileges beyond "View" permissions, nor does it require user interaction beyond sending HTTP POST requests, making it relatively easy to exploit within an environment where an attacker has at least view access. The root cause is insufficient validation of input data submitted to the logging mechanism, allowing injection of arbitrary log entries that can overwhelm system resources.

For European organizations using ZoneMinder for CCTV and surveillance, this vulnerability poses a risk primarily to system availability and operational continuity. An attacker with view permissions—potentially an insider or a compromised low-privilege account—could exploit this flaw to inject excessive log data, causing database performance degradation or storage exhaustion. This could result in denial of service, preventing legitimate access to surveillance footage or system logs critical for security monitoring and incident response. In sectors such as transportation, critical infrastructure, public safety, and corporate security—where ZoneMinder is deployed—such disruption could impair security operations and incident investigations. While confidentiality and integrity impacts are limited since the attacker cannot escalate privileges or directly manipulate video streams, the ability to flood logs with false data could complicate forensic analysis and incident detection. The lack of rate limiting exacerbates the risk, allowing rapid resource consumption. Given the open-source nature of ZoneMinder and its adoption in various European public and private sectors, the threat could affect a broad range of organizations, especially those with limited IT security resources or delayed patching processes.

To mitigate this vulnerability, European organizations should prioritize upgrading ZoneMinder installations to versions 1.36.27 or later, or at least to versions 1.37.24 and above where the issue is resolved. Since no workarounds exist, patching is the primary defense. Additionally, organizations should audit and restrict "View" permissions to only trusted users, minimizing the risk of exploitation by unauthorized or compromised accounts. Implementing network-level controls such as web application firewalls (WAFs) can help detect and block anomalous POST requests targeting the "/zm/index.php" endpoint, especially those with suspicious payloads or high request rates. Monitoring log sizes and database performance metrics can provide early warning signs of exploitation attempts. Organizations should also consider isolating ZoneMinder management interfaces from public networks and enforce strong authentication and access controls. Regular review of user permissions and logs for unusual activity is recommended. Finally, integrating ZoneMinder logs with centralized security information and event management (SIEM) systems can help detect injection attempts and resource exhaustion patterns promptly.