CVE-2025-43859: h11 accepts some malformed Chunked-Encoding bodies
(updated )
A leniency in h11’s parsing of line terminators in chunked-coding message bodies can lead to request smuggling vulnerabilities under certain conditions.
References
- github.com/advisories/GHSA-vqfr-h8mv-ghfj
- github.com/pypa/advisory-database/tree/main/vulns/h11/PYSEC-2026-348.yaml
- github.com/python-hyper/h11/commit/114803a29ce50116dc47951c690ad4892b1a36ed
- github.com/python-hyper/h11/security/advisories/GHSA-vqfr-h8mv-ghfj
- nvd.nist.gov/vuln/detail/CVE-2025-43859
- pypi.org/project/h11
Code Behaviors & Features
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