{"id":"CVE-2026-84379","aliases":["GHSA-h4x7-gw46-3wm6"],"url":"https://o3.security/vulnerability/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.","published":"2026-09-02T17:57:17.092Z","modified":"2026-09-04T03:47:27.062984898Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},"epss":{"score":0.00261,"percentile":0.1774,"asOf":"2026-09-08"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"httpx2","fixedVersion":"2.11.0"}],"fix":{"url":"https://github.com/pydantic/httpx2/commit/de96d810ee4e309d118982fe7084a46a2bcd600d","label":"pydantic/httpx2@de96d81"},"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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-04T03:47:27.062984898Z"}}