CVE-2026-84379

CVE-2026-84379 · HTTPX2: Multipart part header injection via unvalidated file Content-Type and custom headers

This page contains facts from public vulnerability sources. Check the original advisory before updating.

HTTPX2 is a next generation HTTP client for Python. Prior to 2.11.0, FileField.render_headers() in src/httpx2/httpx2/_multipart.py directly interpolates attacker-controlled content_type values and custom headers from the files= three-element (filename, content, content_type) tuple and the files= four-element (filename, content, content_type, headers) tuple into multipart/form-data part headers without validating header names or values. CR or LF characters can terminate a part header, inject additional part headers, or end the part header block early, allowing a downstream multipart parser to treat attacker-supplied lines as genuine headers and potentially alter part semantics or bypass header-based checks. This issue is fixed in version 2.11.0.

CVSS 5.3 · Medium · EPSS 0.3% · Fix available

Published

2026-09-02T17:57:17.092Z

Updated

2026-09-02T18:20:46.599Z

Stack: system · python

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