CVE-2025-52566 HIGH

CVE-2025-52566: llama.cpp tokenizer signed vs. unsigned heap overflow

Vendor Ggml-Org
Product llama.cpp
Weakness CWE-119
Published June 24, 2025
Last update June 24, 2025

CVSS base score

8.6/10
Attack vector Local
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

What the vulnerability does

01Description

llama.cpp is an inference of several LLM models in C/C++. Prior to version b5721, there is a signed vs. unsigned integer overflow in llama.cpp's tokenizer implementation (llama_vocab::tokenize) (src/llama-vocab.cpp:3036) resulting in unintended behavior in tokens copying size comparison. Allowing heap-overflowing llama.cpp inferencing engine with carefully manipulated text input during tokenization process. This issue has been patched in version b5721.

Key dates

02Disclosure timeline

June 24, 2025 CVE published
June 24, 2025 Record updated