# CVE-2025-6638: Regular Expression Denial of Service (ReDoS) in huggingface/transformers

> CVE-2025-6638: Regular Expression Denial of Service (ReDoS) in huggingface/transformers. CVSS 5.3 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2025-6638
Last updated: 2026-06-17T10:02:17Z

- Published: 2025-09-12 10:46 UTC · Updated: 2026-06-17 10:02 UTC · Assigner: @huntr\_ai
- CVSS: 5.3 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- EPSS: 0.55%, 46th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-1333

## Description

A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the Hugging Face Transformers library, specifically affecting the MarianTokenizer's \`remove\_language\_code()\` method. This vulnerability is present in version 4.52.4 and has been fixed in version 4.53.0. The issue arises from inefficient regex processing, which can be exploited by crafted input strings containing malformed language code patterns, leading to excessive CPU consumption and potential denial of service.

## Affected vendors and products

- huggingface: huggingface/transformers

## Tracked companies

- [Hugging Face](https://rewindex.com/company/hugging-face.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2025-6638)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2025-6638)
- [https://github.com/huggingface/transformers/commit/47c34fba5c303576560cb29767efb452ff12b8be](https://github.com/huggingface/transformers/commit/47c34fba5c303576560cb29767efb452ff12b8be)
- [https://huntr.com/bounties/6a6c933f-9ce8-4ded-8b3b-2c1444c61f36](https://huntr.com/bounties/6a6c933f-9ce8-4ded-8b3b-2c1444c61f36)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2025-6638 · Markdown: https://rewindex.com/cve/CVE-2025-6638.md · JSON: https://rewindex.com/api/v1/cves/CVE-2025-6638 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:16:27.771Z