CVE-2026-52132: Llama.cpp vulnerability

Q: Which deployments are exposed?

Only llama.cpp instances started with the --reranking flag are described as affected. The affected request path is the /rerank endpoint.

Q: What does an attacker need to send to trigger the issue?

A remote attacker needs to submit a POST request to /rerank with a negative top_n value. The described result is a denial of service rather than code execution or data exposure.

Q: How can operators recognize an attempted or successful trigger?

The reported failure indicators are a std::bad_alloc condition and an HTTP 500 response from the affected request.

Published Sep 1, 2026

Updated

llama.cpp through commit 97f06e9, when started with the --reranking flag, allows remote attackers to cause a denial of service (std::badalloc and HTTP 500) via a negative topn value in a POST request to /rerank.

Affected Software

1 affected component

llama.cpp<=97f06e9

Event History

Sep 1, 2026

CVE Published

via MITRE·12:00 AM

Data Sourced

via MITRE·12:00 AM

Description

Frequently Asked Questions

Which deployments are exposed?

Only llama.cpp instances started with the --reranking flag are described as affected. The affected request path is the /rerank endpoint.

What does an attacker need to send to trigger the issue?

A remote attacker needs to submit a POST request to /rerank with a negative top_n value. The described result is a denial of service rather than code execution or data exposure.

How can operators recognize an attempted or successful trigger?

The reported failure indicators are a std::bad_alloc condition and an HTTP 500 response from the affected request.