CVE-2025-5197 Regular Expression Denial of Service (ReDoS) in huggingface/transformers
Attackers can cause service disruption and resource exhaustion in Hugging Face Transformers via crafted input triggering catastrophic regex backtracking.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-5197?
CVE-2025-5197 is a medium-severity denial of service vulnerability in huggingface/transformers, published on 6 Aug 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-1333
Which versions are affected by CVE-2025-5197?
3 open source packages ship an affected version, including transformers. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
transformers PyPI | All versions | 4.53.0 |
transformers PyPI | All versions | 4.53.0 |
transformers PyPI | All versions | 4.53.0 |
Products include Huggingface Transformers.
How do I fix CVE-2025-5197?
Upgrade transformers to 4.53.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-5197 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-5197 exists.
Other vulnerabilities in huggingface/transformers
- CVE-2023-7018 Deserialization of Untrusted Data in huggingface/transformers
- CVE-2023-6730 Deserialization of Untrusted Data in huggingface/transformers
- CVE-2024-11393 Hugging Face Transformers MaskFormer Model Deserialization of Untrusted Data Remote Code Execution Vulnerability
- CVE-2024-11394 Hugging Face Transformers Trax Model Deserialization of Untrusted Data Remote Code Execution Vulnerability
- CVE-2026-5241 Policy Bypass in LightGlue Nested Config Resolution in huggingface/transformers
Sources
Also known as GHSA-9356-575x-2w9m, PYSEC-2026-1983.