CVE-2025-2099
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
Package impact
| Ecosystem | Package | Vulnerable | Fixed |
|---|---|---|---|
| PyPI | transformers | <4.50.0 | 4.50.0 |
| PyPI | transformers | <8cb522b4190bd556ce51be04942720650b1a3e57||<4.49.0 | 8cb522b4190bd556ce51be04942720650b1a3e57 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2025-2099
- https://github.com/huggingface/transformers/pull/36648
- https://github.com/huggingface/transformers/commit/8cb522b4190bd556ce51be04942720650b1a3e57
- https://github.com/huggingface/transformers
- https://github.com/pypa/advisory-database/tree/main/vulns/transformers/PYSEC-2025-40.yaml
- https://huntr.com/bounties/97b780f3-ffca-424f-ad5d-0e1c57a5bde4
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.