CVE-2025-5197: Regular Expression Denial of Service (ReDoS) in huggingface/transformers

Severity: medium (CVSS 5.3 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2025-08-06 · updated 2026-06-17
Weakness: CWE-1333

Description

A Regular Expression Denial of Service (ReDoS) vulnerability exists in the Hugging Face Transformers library, specifically in the `convert_tf_weight_name_to_pt_weight_name()` function. This function, responsible for converting TensorFlow weight names to PyTorch format, uses a regex pattern `/[^/]*___([^/]*)/` that can be exploited to cause excessive CPU consumption through crafted input strings due to catastrophic backtracking. The vulnerability affects versions up to 4.51.3 and is fixed in version 4.53.0. This issue can lead to service disruption, resource exhaustion, and potential API service vulnerabilities, impacting model conversion processes between TensorFlow and PyTorch formats.

Affected products

huggingface/transformers: before 4.53.0 — fixed in 4.53.0

How to fix

Upgrade to a fixed version: huggingface/transformers 4.53.0. Check the vendor advisory for mitigations.

References

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