Advisories

sentence-transformers Arbitrary Code Execution on Local Model Load Despite trust_remote_code=False

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severity
critical
date
Affecting
  • sentence-transformers <= 5.5.1, fixed in commit ae1acc3

CWE
  • CWE-94 Improper Control of Generation of Code ('Code Injection')
CVSS
9.3
CVSS V4 Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Credit
Bofei Chen
Description
sentence-transformers contains a security control bypass vulnerability that allows attackers to achieve arbitrary code execution by exploiting a logic flaw in the import_module_class helper within sentence_transformers/util/misc.py, where the guard condition includes an 'or os.path.exists(model_name_or_path)' clause that satisfies the trust gate whenever the supplied path exists on the local filesystem, regardless of the trust_remote_code=False argument. Attackers who can control or influence the contents of a model directory on disk can place malicious Python files such as modeling_*.py referenced via modules.json, causing the code to execute at import time when an application loads the model with SentenceTransformer(path, trust_remote_code=False), bypassing the documented security contract and achieving code execution within the loading process.

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