SB2026021759 - Inefficient regular expression complexity in Hugging Face Transformers library
Published: February 17, 2026
Security Bulletin ID
SB2026021759
Severity
High
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Inefficient regular expression complexity (CVE-ID: CVE-2025-2099)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to insufficient input validation when processing untrusted input with a regular expressions in the in the `preprocess_string()` function of the `transformers.testing_utils` module. A remote attacker can pass specially crafted data to the application and perform regular expression denial of service (ReDos) attack.
Remediation
Install update from vendor's website.