What’s Vulnerable › Vulnerabilities

CVE-2025-6638: Regular Expression Denial of Service (ReDoS) in huggingface/transformers

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2025-09-12 · updated 2026-06-17
• Weakness: CWE-1333

Description

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: 4.52.4

References

• https://github.com/huggingface/transformers/commit/47c34fba5c303576560cb29767efb452ff12b8be
• https://huntr.com/bounties/6a6c933f-9ce8-4ded-8b3b-2c1444c61f36

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