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.
History

Thu, 03 Sep 2026 16:00:00 +0000

Type Values Removed Values Added
First Time appeared Pydantic
Pydantic httpx2
Vendors & Products Pydantic
Pydantic httpx2

Thu, 03 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Wed, 02 Sep 2026 18:00:00 +0000

Type Values Removed Values Added
Description 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.
Title HTTPX2: Multipart part header injection via unvalidated file Content-Type and custom headers
Weaknesses CWE-93
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-09-02T17:57:17.092Z

Updated: 2026-09-02T18:20:46.599Z

Reserved: 2026-09-01T16:27:58.130Z

Link: CVE-2026-84379

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-02T18:21:29.300

Modified: 2026-09-02T19:18:08.010

Link: CVE-2026-84379

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-02T17:57:17Z

Links: CVE-2026-84379 - Bugzilla