CVE-2025-6638: Hugging Face Transformers ReDoS in MarianTokenizer remove_language_code

Summary

CVE-2025-6638 is a Regular Expression Denial of Service (ReDoS) flaw in the Hugging Face Transformers library, affecting the MarianTokenizer's `remove_language_code()` method in version 4.52.4. Inefficient regex processing lets crafted input strings containing malformed language code patterns drive excessive CPU consumption, which can cause a denial of service. The weakness is classified as CWE-1333, and the fix is reported in version 4.53.0.

Mitigation

Fixed in 4.53.0.

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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