CVE-2025-2099: Regular Expression Denial of Service (ReDoS) in huggingface/transformers
Description
A vulnerability in the `preprocess_string()` function of the `transformers.testing_utils` module in huggingface/transformers version v4.48.3 allows for a Regular Expression Denial of Service (ReDoS) attack. The regular expression used to process code blocks in docstrings contains nested quantifiers, leading to exponential backtracking when processing input with a large number of newline characters. An attacker can exploit this by providing a specially crafted payload, causing high CPU usage and potential application downtime, effectively resulting in a Denial of Service (DoS) scenario.
Classification
CVE ID: CVE-2025-2099
CVSS Base Severity: MEDIUM
CVSS Base Score: 5.3
CVSS Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Problem Types
CWE-1333 Inefficient Regular Expression ComplexityAffected Products
Vendor: huggingface
Product: huggingface/transformers
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.05% (probability of being exploited)
EPSS Percentile: 15.22% (scored less or equal to compared to others)
EPSS Date: 2025-06-17 (when was this score calculated)
References
https://nvd.nist.gov/vuln/detail/CVE-2025-2099https://huntr.com/bounties/97b780f3-ffca-424f-ad5d-0e1c57a5bde4
https://github.com/huggingface/transformers/commit/8cb522b4190bd556ce51be04942720650b1a3e57