HighVulnerability
CVE-2025-6921: huggingface/transformers ReDoS in AdamWeightDecay optimizer via regex patterns
- Source
- NVD(opens in a new tab)
- Identifier
- CVE-2025-6921
- Published
- Record updated
- Affected
- transformers < 4.53.0
- Fixed in
- 4.53.0
- released June 26, 2025, 89 days before disclosure
- Known exploitation
- Not listed in the CISA Known Exploited Vulnerabilities catalog at the last check.
- EPSS
- 0.5%
Summary
CVE-2025-6921 affects the huggingface/transformers library before version 4.53.0. Malicious regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists of the AdamWeightDecay optimizer, processed by the _do_use_weight_decay method, can trigger catastrophic backtracking during re.search. An attacker who controls those patterns can drive CPU use to 100%, hanging the machine learning task and making services unresponsive.
Mitigation
The source does not state a fix yet. Check the original advisory for updates.
Affected packages in the Exposure Registry
Matched by package name and ecosystem. Each entry shows whether the package delegates to a language model and how many tracked packages depend on it.
- transformersPyPILLM dependency since 2016-08-17 · 141 tracked dependents
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