CVE-2025-6638: transformers — Exploit & Fix

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.

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CVSS v3.1 Score

7.5

HIGH

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

Weakness Type (CWE)

CWE-1333 CWE-1333

Affected Products

Vendor	Product	Versions
huggingface	transformers	All

References

Advisories & Patches

https://github.com/huggingface/transformers/commit/47c34fba5c303576560cb29767efb452ff12b8be

Exploits

https://huntr.com/bounties/6a6c933f-9ce8-4ded-8b3b-2c1444c61f36

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2025-6638? +

CVE-2025-6638 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-6638? +

CVE-2025-6638 affects products from huggingface, specifically: transformers. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-6638? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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