Buffer Overflow Vulnerability in NGINX Open Source and NGINX Plus

CVE-2026-27654

What is CVE-2026-27654?

CVE-2026-27654 is a critical vulnerability identified within the NGINX Open Source and NGINX Plus web servers, specifically within the ngx_http_dav_module module. NGINX, a popular web server and reverse proxy server, is widely used for serving web applications and providing load balancing. This vulnerability enables the potential for a buffer overflow within the NGINX worker process when specific DAV module methods—such as MOVE or COPY—are employed, particularly with configurations that include non-regular expression location configurations and alias directives. Such exploitation could lead to the termination of the NGINX worker process or allow unauthorized modification of file names beyond the designated document root. This presents a risk for organizations utilizing NGINX since it may result in downtime, disruption of web services, and data integrity issues.

Potential impact of CVE-2026-27654

1. Service Disruption: Exploitation of this vulnerability can cause the NGINX worker process to terminate, potentially leading to downtime and disruption of critical web services hosted on affected systems.

2. Unauthorized File Manipulation: Attackers could leverage this vulnerability to modify source and destination file names outside of the intended directory structures, posing risks to data integrity and unauthorized access to files.

3. Limited Privilege Escalation: While the NGINX worker process operates with low privileges, any successful exploitation could lead to further attacks or system misconfigurations, compounding security risks.

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