{"id":"CVE-2026-39805","aliases":["EEF-CVE-2026-39805","GHSA-c67r-gc9j-2qf7"],"url":"https://o3.security/vulnerability/CVE-2026-39805","summary":"CL.CL HTTP request smuggling via duplicate Content-Length in bandit","details":"Inconsistent Interpretation of HTTP Requests vulnerability in mtrudel bandit allows HTTP request smuggling via duplicate Content-Length headers.\n\n'Elixir.Bandit.Headers':get_content_length/1 in lib/bandit/headers.ex uses List.keyfind/3, which returns only the first matching header. When a request contains two Content-Length headers with different values, Bandit silently accepts it, uses the first value to read the body, and dispatches the remaining bytes as a second pipelined request on the same keep-alive connection. RFC 9112 §6.3 requires recipients to treat this as an unrecoverable framing error.\n\nWhen Bandit sits behind a proxy that picks the last Content-Length value and forwards the request rather than rejecting it, an unauthenticated attacker can smuggle requests past edge WAF rules, path-based ACLs, rate limiting, and audit logging.\n\nThis issue affects bandit: before 1.11.0.","published":"2026-05-01T20:34:29.400Z","modified":"2026-08-07T11:31:33.928565300Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Hex","name":"bandit","fixedVersion":"1.11.0"}],"fix":{"url":"https://github.com/mtrudel/bandit/commit/f2ca636eb6df385219957e8934e9fc6efa1630d1","label":"mtrudel/bandit@f2ca636"},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-39805.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-39805"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39805.json"},{"type":"ADVISORY","url":"https://github.com/mtrudel/bandit/security/advisories/GHSA-c67r-gc9j-2qf7"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-39805"},{"type":"FIX","url":"https://github.com/mtrudel/bandit/commit/f2ca636eb6df385219957e8934e9fc6efa1630d1"},{"type":"PACKAGE","url":"https://github.com/mtrudel/bandit"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:31:33.928565300Z"}}