CVE-2026-52132

A flaw was found in llama.cpp. A remote attacker can exploit this vulnerability when the application is started with the --reranking flag. By sending a POST request to the /rerank endpoint with a negative top_n value, the attacker can cause a std::bad_alloc error and an HTTP 500 response, leading to a Denial of Service (DoS).

A flaw was found in llama.cpp when running in server mode with reranking enabled. An unauthenticated remote attacker can issue a POST request to the /rerank endpoint containing a negative top_n parameter value. This invalid input triggers an uncontrolled memory allocation attempt (std::bad_alloc), leading to an application exception or process crash that results in a denial of service.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Disable the --reranking command-line flag if reranking capabilities are not required. If reranking functionality must remain enabled, configure an upstream reverse proxy or API gateway to validate POST request payloads to /rerank and block requests containing negative top_n values.