Inefficient regular expression complexity in transformers - CVE-2025-2099
Published: February 17, 2026
Vulnerability identifier: #VU122993
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2025-2099
CWE-ID: CWE-1333
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: huggingface
Affected software:
transformers
transformers
Detailed vulnerability description
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.
How to mitigate CVE-2025-2099
Cybersecurity Help is currently unaware of any official solution to address this vulnerability..