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

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

No CVSS v2

This CVE is not in the KEV list.

Exploitation poc

Automatable yes

Technical Impact partial

Affected Vendors & Products

Vendors Products
Huggingface
  • Transformers

Configuration 1 [-]

cpe:2.3:a:huggingface:transformers:4.52.4:*:*:*:*:*:*:*

No data.

References
Link Providers
https://github.com/huggingface/transformers/commit/47c34fba5c303576560cb29767efb452ff12b8be cve-icon cve-icon cve-icon
https://huntr.com/bounties/6a6c933f-9ce8-4ded-8b3b-2c1444c61f36 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-6638 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-6638 cve-icon
History

Tue, 21 Oct 2025 13:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:huggingface:transformers:4.52.4:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Mon, 15 Sep 2025 10:45:00 +0000

Type Values Removed Values Added
First Time appeared Huggingface
Huggingface transformers
Vendors & Products Huggingface
Huggingface transformers

Sat, 13 Sep 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 threat_severity

Moderate

Fri, 12 Sep 2025 12:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Fri, 12 Sep 2025 11:00:00 +0000

Type Values Removed Values Added
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.
Title Regular Expression Denial of Service (ReDoS) in huggingface/transformers
Weaknesses CWE-1333
References
Metrics cvssV3_0

{'score': 5.3, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}
cve-icon MITRE

Status: PUBLISHED

Assigner: @huntr_ai

Published: 2025-09-12T10:46:07.934Z

Updated: 2025-09-12T11:52:53.854Z

Reserved: 2025-06-25T14:07:29.841Z

Link: CVE-2025-6638

cve-icon Vulnrichment

Updated: 2025-09-12T11:52:48.581Z

cve-icon NVD

Status : Analyzed

Published: 2025-09-12T11:15:31.770

Modified: 2025-10-21T13:33:08.580

Link: CVE-2025-6638

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-09-12T10:46:07Z

Links: CVE-2025-6638 - Bugzilla