Vulnerability in Huggingface Huggingface/transformers

CVE-2025-6638

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.

Vulnerability class: ReDoS (Regular Expression Denial of Service)

EPSS: 0.005 (39.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-6638?
CVE-2025-6638 is a high-severity vulnerability in Huggingface Huggingface/transformers, classified under Inefficient Regular Expression Complexity. CVSS score: 7.5/10. Published 2025-09-12.
How severe is CVE-2025-6638?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2025-6638 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.