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.
Published: 2025-09-23
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
EUVD EUVD EUVD-2025-30889 Hugging Face Transformers vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer
Github GHSA Github GHSA GHSA-4w7r-h757-3r74 Hugging Face Transformers vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer
History

Fri, 10 Oct 2025 21:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:huggingface:transformers:*:*:*:*:*:*:*:*
Metrics 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'}

 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'}

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'}

Subscriptions

Huggingface Transformers
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 : Analyzed

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

Modified: 2025-10-10T21:31:30.230

Link: CVE-2025-6921

cve-icon Redhat

Severity : Moderate

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

Links: CVE-2025-6921 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-09-25T08:22:22Z

Weaknesses