HTTPX2: Multipart part header injection via unvalidated file Content-Type and custom headers

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-84379
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-02 18:21:29 UTC
Updated2026-09-02 19:18:08 UTC
DescriptionHTTPX2 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.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Problem Types: CWE-93 | CWE-93 CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
3.1CNADECLARED5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Pydantic Httpx2 affected < 2.11.0 Not specified

References

ReferenceSourceLinkTags
github.com/pydantic/httpx2/releases/tag/v2.11.0 [email protected] github.com
github.com/pydantic/httpx2/security/advisories/GHSA-h4x7-gw46-3wm6 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/pydantic/httpx2/pull/1142 [email protected] github.com
github.com/pydantic/httpx2/commit/de96d810ee4e309d118982fe7084a46a2bcd600d [email protected] github.com
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