Mod_qos implements response-body substring matching. Inspecting a response body can trigger an out-of-bounds read due to improper boundary checks, allowing an unauthenticated remote attacker to craft responses that cause the module to read memory beyond the allocated buffer and crash the Apache worker process, resulting in a denial of service.

The affected product is Mod_qos, a third‑party module for Apache HTTP Server developed by pbuchbinder. The vulnerability does not specify an affected version range, so any deployment that includes Mod_qos may be vulnerable until a patched version is installed. The module is commonly found in Apache installations that use custom response handling.

The CVSS score of 3.7 indicates a low‑to‑moderate severity exploit, and the EPSS score is not available. The vulnerability is not listed in the CISA KEV catalog. An attacker can exploit the flaw remotely by sending specially crafted server responses without authentication, causing a crash of an Apache worker and a denial of service that impacts service availability. The impact is limited to the web server process, with no evidence of information disclosure or code execution.