🚨 CVE-2026-84380
HTTPX2 is a next generation HTTP client for Python. Prior to 2.11.0, Request._prepare() in src/httpx2/httpx2/_models.py can add a body-derived Content-Length header to a request that already contains a caller-supplied Transfer-Encoding header because its setdefault() processing checks each default header independently rather than treating the two framing headers as mutually exclusive. Fixed-size byte, JSON, form, and known-length multipart bodies can therefore be serialized over HTTP/1.1 with both headers, allowing request smuggling or connection desynchronization when downstream intermediaries disagree about which framing header takes precedence. This issue is fixed in version 2.11.0.
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GitHub
Respect explicit Transfer-Encoding headers (#1137) · pydantic/httpx2@829b93a
A next generation HTTP client for Python. 🦋. Contribute to pydantic/httpx2 development by creating an account on GitHub.
September 2, 2026 34
