CVE-2026-84380
mediumHTTPX2 is a next generation HTTP client for Python.
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/pydantic/httpx2/commit/829b93a2393212996f613e635261f777d9ec6eab security-advisories@github.com
- https://github.com/pydantic/httpx2/pull/1137 security-advisories@github.com
- https://github.com/pydantic/httpx2/releases/tag/v2.11.0 security-advisories@github.com
- https://github.com/pydantic/httpx2/security/advisories/GHSA-pf96-p4fj-6566 security-advisories@github.com