CVE-2025-3264 Regular Expression Denial of Service (ReDoS) in huggingface/transformers
Attackers can cause resource exhaustion and service disruption 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-2025-3264?
CVE-2025-3264 is a medium-severity denial of service vulnerability in huggingface/transformers, published on 7 Jul 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 was discovered in the Hugging Face Transformers library, specifically in the `get_imports()` function within `dynamic_module_utils.py`. This vulnerability affects versions 4.49.0 and is fixed in version 4.51.0. The issue arises from a regular expression pattern `\s*try\s*:.*?except.*?:` used to filter out try/except blocks from Python code, which can be exploited to cause excessive CPU consumption through crafted input strings due to catastrophic backtracking. This vulnerability can lead to remote code loading disruption, resource exhaustion in model serving, supply chain attack vectors, and development pipeline disruption.
Weakness: CWE-1333
Which versions are affected by CVE-2025-3264?
3 open source packages ship an affected version, including transformers. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
transformers PyPI | All versions | 4.51.0 |
transformers PyPI | All versions | 4.51.0 |
transformers PyPI | All versions | 4.51.0 |
Products include Huggingface Transformers.
How do I fix CVE-2025-3264?
Upgrade transformers to 4.51.0 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-2025-3264 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-3264 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-jjph-296x-mrcr, PYSEC-2026-1985.