CVE-2025-2099: Huggingface Transformers

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days.

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.

Affected products

• Huggingface Transformers: up to and including 4.48.3

Published 2025-05-19. Last modified 2026-06-17.