The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer. The vulnerability arises from the _do_use_weight_decay method, which processes user-controlled regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists. Malicious regular expressions can cause catastrophic backtracking during the re.search call, leading to 100% CPU utilization and a denial of service. This issue can be exploited by attackers who can control the patterns in these lists, potentially causing the machine learning task to hang and rendering services unresponsive.
History

Thu, 25 Sep 2025 08:30:00 +0000

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

Wed, 24 Sep 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

threat_severity

Moderate


Tue, 23 Sep 2025 15:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Tue, 23 Sep 2025 14:00:00 +0000

Type Values Removed Values Added
Description The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer. The vulnerability arises from the _do_use_weight_decay method, which processes user-controlled regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists. Malicious regular expressions can cause catastrophic backtracking during the re.search call, leading to 100% CPU utilization and a denial of service. This issue can be exploited by attackers who can control the patterns in these lists, potentially causing the machine learning task to hang and rendering services unresponsive.
Title Regular Expression Denial of Service (ReDoS) in huggingface/transformers
Weaknesses CWE-400
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:

Updated: 2025-09-23T14:56:29.038Z

Reserved: 2025-06-30T09:44:12.092Z

Link: CVE-2025-6921

cve-icon Vulnrichment

Updated: 2025-09-23T14:56:25.327Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-09-23T14:15:41.387

Modified: 2025-09-24T18:11:24.520

Link: CVE-2025-6921

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-09-23T13:56:15Z

Links: CVE-2025-6921 - Bugzilla