# CVE-2026-84379

## Summary

- **CVE ID:** CVE-2026-84379
- **Severity:** MEDIUM
- **CVSS Score:** 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)
- **CWE:** CWE-93
- **Published:** Sep 2, 2026
- **Last Modified:** Sep 2, 2026

## 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.

## Affected Products

- pydantic — httpx2 (< 2.11.0)

## References

- [CNA](https://github.com/pydantic/httpx2/security/advisories/GHSA-h4x7-gw46-3wm6)
- [CNA](https://github.com/pydantic/httpx2/pull/1142)
- [CNA](https://github.com/pydantic/httpx2/commit/de96d810ee4e309d118982fe7084a46a2bcd600d)
- [CNA](https://github.com/pydantic/httpx2/releases/tag/v2.11.0)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.26%
- **EPSS Percentile:** 17.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._