CVE-2025-6921
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.
- CVSS 3.1
- 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.5% chance of exploitation in the next 30 days; higher than 43% of CVEs (scores of 2026-10-25)
- CWE
- CWE-400
- Published
- Modified
- Record from
- the NVD, synced
Affected
- huggingface:transformers
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-4w7r-h757-3r74 | PyPI | transformers | <4.53.0 | 4.53.0 |
| PYSEC-2026-1980 | PyPI | transformers | <4.53.0 | 4.53.0 |