CVE-2025-6638: Huggingface Transformers

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the Hugging Face Transformers library, specifically affecting the MarianTokenizer's `remove_language_code()` method. This vulnerability is present in version 4.52.4 and has been fixed in version 4.53.0. The issue arises from inefficient regex processing, which can be exploited by crafted input strings containing malformed language code patterns, leading to excessive CPU consumption and potential denial of service.

Affected products

• Huggingface Transformers: version 4.52.4 only

Published 2025-09-12. Last modified 2026-06-17.