CVE-2025-6638

Name: CVE-2025-6638
Creator: NVD / NIST
Published: 2025-09-12T11:15:31.77+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.49%

Last modified Jun 17, 2026

CVE-2025-6638 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.49% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.49%

38.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-1333

Affected Software

Vendor	Product	Versions
Huggingface	Transformers	4.52.4

References

https://github.com/huggingface/transformers/commit/47c34fba5c303576560cb29767efb452ff12b8bePatch
https://huntr.com/bounties/6a6c933f-9ce8-4ded-8b3b-2c1444c61f36Exploit, Third Party Advisory

Timeline

Published: Sep 12, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-6638?

How severe is CVE-2025-6638?

CVE-2025-6638 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.49% probability of exploitation in the next 30 days.

How do I fix CVE-2025-6638?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-6638?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST