How severe is CVE-2025-6638?

CVE-2025-6638 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2025-6638 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-6638?

CVE-2025-6638 affects Huggingface Transformers. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-6638?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-6638 have an EU (EUVD) identifier?

Yes. CVE-2025-6638 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-29032.

When was CVE-2025-6638 published?

CVE-2025-6638 was published on 2025-09-12 and last updated on 2026-06-17.

CVE-2025-6638

CVE-2025-6638 is a high-severity vulnerability in Huggingface Transformers with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1333.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-29032
Weakness: CWE-1333
Affected product: Huggingface Transformers
Published: 2025-09-12
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2025-6638?: 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.
How severe is CVE-2025-6638?: CVE-2025-6638 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-6638 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-6638?: CVE-2025-6638 affects Huggingface Transformers. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-6638?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-6638 have an EU (EUVD) identifier?: Yes. CVE-2025-6638 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-29032.
When was CVE-2025-6638 published?: CVE-2025-6638 was published on 2025-09-12 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:huggingface:transformers:4.52.4:*:*:*:*:*:*:*

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