TransformersGHSA-qq3j-4f4f-9583
Hugging Face Transformers Regular Expression Denial of Service
Medium5.3CVE-2025-2099 · Published May 19, 2025 · updated Sep 25, 2025
A Regular Expression Denial of Service (ReDoS) exists in the `preprocess_string()` function of the `transformers.testing_utils` module. In versions **before 4.50.0**, the regex used to process code blocks in docstrings contains nested quantifiers that can trigger catastrophic backtracking when given inputs with many newline characters. An attacker who can supply such input to `preprocess_string()` (or code paths that call it) can force excessive CPU usage and degrade availability. **Fix:** released in **4.50.0**, which rewrites the regex to avoid the inefficient pattern. ([GitHub][1]) * **Affected:** `< 4.50.0` * **Patched:** `4.50.0`
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| transformers PyPI | < 4.50.0 | 4.50.0 |
Details and references
- CVSS 3.0
- CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Severity from
- GitHub (reviewed advisory)
- Weakness
- CWE-1333
- Also known as
- CVE-2025-2099, PYSEC-2025-40
- nvd.nist.gov/vuln/detail/CVE-2025-2099
- github.com/huggingface/transformers/pull/36648
- github.com/huggingface/transformers/commit/8cb522b4190bd556ce51be04942720650b1a3e57
- github.com/huggingface/transformers
- github.com/pypa/advisory-database/tree/main/vulns/transformers/PYSEC-2025-40.yaml
- huntr.com/bounties/97b780f3-ffca-424f-ad5d-0e1c57a5bde4
More Transformers advisories
All Transformers| Date | Advisory | Severity | Fixed in |
|---|---|---|---|
| Jul 112025 | Transformers is vulnerable to ReDoS attack through its DonutProcessor class Medium5.3Jul 11, 2025 | Medium5.3 | 4.52.1 |
| Jul 72025 | Transformers's ReDoS vulnerability in get_configuration_file can lead to catastrophic backtrackingMedium5.3Jul 7, 2025 | Medium5.3 | 4.51.0 |
| Jul 72025 | Transformers's Improper Input Validation vulnerability can be exploited through username injectionLow3.5Jul 7, 2025 | Low3.5 | 4.52.1 |
| Jul 72025 | Transformers vulnerable to ReDoS attack through its get_imports() functionMedium5.3Jul 7, 2025 | Medium5.3 | 4.51.0 |
| Jul 72025 | Transformers vulnerable to ReDoS attack through its SETTING_RE variableMedium5.3Jul 7, 2025 | Medium5.3 | 4.51.0 |
| Apr 292025 | Transformers Regular Expression Denial of Service (ReDoS) vulnerabilityMedium4.3Apr 29, 2025 | Medium4.3 | 4.50.0 |