CVE-2026-7669
MEDIUMsgl-project SGLang HuggingFace Transformer hf_transformers_utils.py get_tokenizer deserialization
Title source: cnaExploitation Summary
EIP tracks 1 public exploit for CVE-2026-7669. PoCs published by gouldnicholas.
AI-analyzed exploit summary This repository contains a functional exploit PoC for CVE-2026-7669, demonstrating how SGLang silently overrides `trust_remote_code=False` to `True`, leading to arbitrary code execution via a malicious tokenizer. The PoC includes detailed reproduction steps, a Docker environment, and a comprehensive ledger of claims to verify the vulnerability.
Description
A vulnerability was detected in sgl-project SGLang up to 0.5.9. Impacted is the function get_tokenizer of the file python/sglang/srt/utils/hf_transformers_utils.py of the component HuggingFace Transformer Handler. The manipulation of the argument trust_remote_code with the input False as part of Boolean results in code injection. The attack can be executed remotely. A high complexity level is associated with this attack. The exploitability is considered difficult. In get_tokenizer(), when the caller passes trust_remote_code=False and HuggingFace transformers v5 returns a TokenizersBackend instance (the generic fallback for tokenizer classes not in the registry), SGLang silently re-invokes AutoTokenizer.from_pretrained with trust_remote_code=True, overriding the caller's explicit security setting. A model repository containing a malicious tokenizer.py referenced via auto_map in tokenizer_config.json will execute arbitrary Python in the SGLang process during this second call. No log line or warning is emitted. The override affects all current SGLang versions because transformers==5.3.0 is pinned in pyproject.toml. Both tokenizer_mode="auto" and tokenizer_mode="slow" are affected. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Exploits (1)
This repository contains a functional exploit PoC for CVE-2026-7669, demonstrating how SGLang silently overrides `trust_remote_code=False` to `True`, leading to arbitrary code execution via a malicious tokenizer. The PoC includes detailed reproduction steps, a Docker environment, and a comprehensive ledger of claims to verify the vulnerability.
References (4)
Scores
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L