gcdRadar
archive/Patch now/AIR-2025-0345
closedclosed 23 Sep 2025Patch now2 Disclosed vulnerabilityAI

CVE-2025-6921: Hugging Face Transformers vulnerable to ReDoS in optimizer

transformers

The Hugging Face transformers library contained a regular expression denial of service vulnerability in the AdamWeightDecay optimizer. A patch has been released in version 4.53.0 to resolve the issue.

disclosed CVENo confirmed exploitation, so this record is tracked as a disclosed vulnerability and not counted as an incident. It moves into the counts if CISA or the vendor confirms exploitation. Why

CVSS
5.3
EPSS
0.01 · top 56% · 2026-11-13
EPSS scores by FIRST
fix status
Fix status unknown
first report
23 Sep 2025
last update
23 Sep 2025
CVE ids
CVE-2025-6921other records

Timeline · 1

  1. 23 Sep 2025CVE-2025-6921: Hugging Face Transformers vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer

Sources · 1

Advisories and databases

  1. 2025-09-23
    CVE-2025-6921: Hugging Face Transformers vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer
    GitHub Advisory Database · github.com/advisories/GHSA-4w7r-h757-3r74

Titles and links belong to their publishers. The summary above is written by gcdRadar in its own words; data is CC BY-SA 4.0.

Classification

lane
Patch now
AI role
Attack on AI
categories
Infrastructure vulnerability
severity
2 · Disclosed vulnerability
fix status
Fix status unknown
targets
Framework / tooling
owasp llm top 10
LLM03:2025 Supply Chain
mitre atlas
no technique for these categories
tags
redoshuggingface
dates
happened 23 Sep 2025 · first reported 23 Sep 2025
origin
GitHub Advisory Database
Vulnerability record from NVD / the GitHub Advisory Database. This product uses the NVD API but is not endorsed or certified by the NVD.
record
confidence 0.95 · created 2026-10-18 07:00Z · updated 2026-10-18 07:00Z

Lane, AI role, categories and severity come from the classifier; the OWASP and ATLAS rows are derived from the categories. How these are assigned

Copy a brief

This record as a short Markdown brief, for a ticket, a chat or a coding agent.

the brief as text
# CVE-2025-6921: Hugging Face Transformers vulnerable to ReDoS in optimizer

https://gcdradar.vercel.app/incidents/cve-2025-6921-hugging-face-transformers-vulnerable-to-redos · AIR-2025-0345 · closed 2025-09-23

- Lane: Patch now
- Severity: 2 (Disclosed vulnerability)
- Fix status: Fix status unknown
- First reported: 2025-09-23
- AI role: Attack on AI
- Products: transformers
- CVE ids: CVE-2025-6921
- CVSS: 5.3

## Summary

The Hugging Face transformers library contained a regular expression denial of service vulnerability in the AdamWeightDecay optimizer. A patch has been released in version 4.53.0 to resolve the issue.

## What to do

No action recorded; read the sources below and the vendor's advisory.

## Latest updates

- 2025-09-23: CVE-2025-6921: Hugging Face Transformers vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer (https://github.com/advisories/GHSA-4w7r-h757-3r74)

## Sources

- 2025-09-23 GitHub Advisory Database: CVE-2025-6921: Hugging Face Transformers vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer https://github.com/advisories/GHSA-4w7r-h757-3r74

Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.

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