{"id":"CVE-2026-84379","summary":"HTTPX2: Multipart part header injection via unvalidated file Content-Type and custom headers","details":"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.","aliases":["GHSA-h4x7-gw46-3wm6","PYSEC-2026-3848"],"modified":"2026-09-11T03:30:33.804692127Z","published":"2026-09-02T17:57:17.092Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84379.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-93"]},"references":[{"type":"WEB","url":"https://github.com/pydantic/httpx2/releases/tag/v2.11.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84379.json"},{"type":"ADVISORY","url":"https://github.com/pydantic/httpx2/security/advisories/GHSA-h4x7-gw46-3wm6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-84379"},{"type":"FIX","url":"https://github.com/pydantic/httpx2/commit/de96d810ee4e309d118982fe7084a46a2bcd600d"},{"type":"FIX","url":"https://github.com/pydantic/httpx2/pull/1142"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/pydantic/httpx2","events":[{"introduced":"0"},{"fixed":"de96d810ee4e309d118982fe7084a46a2bcd600d"},{"fixed":"2b13fa92e4181d5e0f56772205360b2aa12f109d"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"2.11.0"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v2.10.0","v2.9.1","v2.9.0","v2.8.0","v2.7.0","v2.6.0","v2.5.0","v2.4.0","v2.3.0","v2.2.0","v2.1.0","v2.0.0","v2.0.0b1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-84379.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}