Hugging Face Transformers Regular Expression Denial of Service (ReDoS) vulnerability
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 software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | transformers | < 4.53.0 | 4.53.0 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2025-5197
- https://github.com/huggingface/transformers/commit/701caef704e356dc2f9331cc3fd5df0eccb4720a
- https://github.com/huggingface/transformers/commit/944b56000be5e9b61af8301aa340838770ad8a0b
- https://github.com/huggingface/transformers
- https://huntr.com/bounties/3f8b3fd0-166b-46e7-b60f-60dd9d2678bf
- https://pypi.org/project/transformers
- https://github.com/advisories/GHSA-9356-575x-2w9m
- CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L- Weakness (CWE)
CWE-1333- Platform
- Python (PyPI)
- Package
transformers- Disclosed
- 06.08.2025
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-1983 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-9356-575x-2w9m - CC BY 4.0
Vulnerability history: transformers
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 32
- First → latest
- 05.2023 09.2026
- Without a fix
- 9
- Exploited in attacks
- 0
Severity breakdown
- High 18
- Medium 12
- Low 2
Disclosures per year
- 2023: 3
- 2024: 4
- 2025: 20
- 2026: 5
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Hugging Face Transformers Regular Expression Denial of Service (ReDoS) vulnerability this entry
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