PYSEC-2026-1979
Transformers vulnerable to ReDoS attack through its SETTING_RE variable
Quick fix
PYSEC-2026-1979 — transformers: upgrade to the fixed version with the command below.
pip install --upgrade 'transformers>=4.51.0'Details
A Regular Expression Denial of Service (ReDoS) vulnerability was discovered in the huggingface/transformers repository, specifically in version 4.49.0. The vulnerability is due to inefficient regular expression complexity in the `SETTING_RE` variable within the `transformers/commands/chat.py` file. The regex contains repetition groups and non-optimized quantifiers, leading to exponential backtracking when processing 'almost matching' payloads. This can degrade application performance and potentially result in a denial-of-service (DoS) when handling specially crafted input strings. The issue is fixed in version 4.51.0.
Are you affected?
Enter the version of the package you're using.
Affected packages
4.49.0Fixed in: 4.51.0pip install --upgrade 'transformers>=4.51.0'References
- https://nvd.nist.gov/vuln/detail/CVE-2025-3262[ADVISORY]
- https://github.com/huggingface/transformers/commit/0720e206c6ba28887e4d60ef60a6a089f6c1cc76[WEB]
- https://github.com/huggingface/transformers/commit/126abe3461762e5fc180e7e614391d1b4ab051ca[WEB]
- https://github.com/huggingface/transformers[PACKAGE]
- https://huntr.com/bounties/ecf5ccc4-39e7-4fb3-b547-14a41d31a184[WEB]
- https://pypi.org/project/transformers[PACKAGE]
- https://github.com/advisories/GHSA-489j-g2vx-39wf[ADVISORY]