CVE-2025-3263 Regular Expression Denial of Service (ReDoS) in huggingface/transformers
Attackers can cause denial of service in applications using the Hugging Face Transformers library by triggering catastrophic backtracking in a regular expression.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-3263?
CVE-2025-3263 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_configuration_file()` function within the `transformers.configuration_utils` module. The affected version is 4.49.0, and the issue is resolved in version 4.51.0. The vulnerability arises from the use of a regular expression pattern `config\.(.*)\.json` that can be exploited to cause excessive CPU consumption through crafted input strings, leading to catastrophic backtracking. This can result in model serving disruption, resource exhaustion, and increased latency in applications using the library.
Weakness: CWE-1333
Which versions are affected by CVE-2025-3263?
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-2025-3263?
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-2025-3263 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-3263 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-q2wp-rjmx-x6x9, PYSEC-2026-1987.