{"id":"CVE-2026-114216","aliases":["EEF-CVE-2026-114216","EUVD-2026-109820","GHSA-w5wc-g2hc-g7m2","UBUNTU-CVE-2026-114216"],"status":"published","title":"Chunk extensions accept bare LF and CR, enabling request smuggling in Bandit","description":"Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to smuggle a second request past a front-end proxy via a chunk extension that contains a bare LF.\n\nThe chunked reader in lib/bandit/http1/socket.ex takes the chunk-size line to be everything up to the first CRLF and discards everything after ; without checking it against the RFC 9112 chunk-ext grammar, so bare LF, bare CR and other control bytes pass. A proxy that ends the size line at a bare LF reads 2;\\nxx\\r\\n40\\r\\n... as one request whose second chunk holds a GET /admin, while Bandit ends the body early and dispatches GET /admin as a separate pipelined request. Deployments without such a proxy in front of Bandit are not affected.\n\nThis issue affects bandit: from 1.12.4 before 1.14.0.","severity":{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00602,"percentile":0.4933,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-444"],"published":"2026-10-26T13:30:41Z","modified":"2026-10-28T20:17:45Z","fixes":[{"ecosystem":"Hex","package":"bandit","fixed_in":["1.14.0"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Hex","package":"bandit","ranges":[{"type":"SEMVER","events":[{"introduced":"1.12.4"},{"fixed":"1.14.0"}]}],"versions":["1.12.4","1.12.5","1.13.0","1.13.1"]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"bandit","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.13.2-1","0.13.2-3"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"bandit","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.0-0ubuntu2"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"bandit","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.1-3","1.6.2-1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"bandit","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6.2-1"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"bandit","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6.2-3"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"bandit","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.7.10-3","1.9.4-1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"bandit","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.7.10-2","1.7.10-3"]}],"products":[{"vendor":"mtrudel","product":"bandit"}],"references":[{"url":"https://github.com/mtrudel/bandit/security/advisories/GHSA-w5wc-g2hc-g7m2","tags":["vendor-advisory","related","advisory"]},{"url":"https://cna.erlef.org/cves/CVE-2026-114216.html","tags":["related","web"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-114216","tags":["related","web"]},{"url":"https://github.com/mtrudel/bandit/commit/c31e9e3c76dcbfc239a96eabed5341ced7885ae5","tags":["related","fix","web","report"]},{"url":"https://github.com/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7a","tags":["patch","fix","report"]},{"url":"https://github.com","tags":["web","report"]},{"url":"https://repo.hex.pm","tags":["web","report"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/114xxx/CVE-2026-114216.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-114216","tags":["advisory"]},{"url":"https://github.com/mtrudel/bandit","tags":["package","report"]},{"url":"https://hex.pm/packages/bandit","tags":["package","report"]},{"url":"https://ubuntu.com/security/CVE-2026-114216","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-114216","tags":["report"]},{"url":"https://cna.erlef.org/cves/cve-2026-114216.html","tags":["report"]},{"url":"https://github.com/mtrudel/bandit/security/advisories/ghsa-w5wc-g2hc-g7m2","tags":["report"]},{"url":"https://github.com/cveproject/cvelistv5/tree/main/cves/2026/114xxx/cve-2026-114216.json","tags":["report"]},{"url":"https://nvd.nist.gov/vuln/detail/cve-2026-114216","tags":["report"]},{"url":"https://osv.dev/vulnerability/eef-cve-2026-114216","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-114216","title":"Chunk extensions accept bare LF and CR, enabling request smuggling in Bandit","description":"Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to smuggle a second request past a front-end proxy via a chunk extension that contains a bare LF.\n\nThe chunked reader in lib/bandit/http1/socket.ex takes the chunk-size line to be everything up to the first CRLF and discards everything after ; without checking it against the RFC 9112 chunk-ext grammar, so bare LF, bare CR and other control bytes pass. A proxy that ends the size line at a bare LF reads 2;\\nxx\\r\\n40\\r\\n... as one request whose second chunk holds a GET /admin, while Bandit ends the body early and dispatches GET /admin as a separate pipelined request. Deployments without such a proxy in front of Bandit are not affected.\n\nThis issue affects bandit: from 1.12.4 before 1.14.0.","status":"published","published":"2026-10-26T13:30:41.225Z","modified":"2026-10-26T15:35:51.933Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium","assessor":"cna"}],"cwes":["CWE-444"],"updated_at":"2026-11-02T13:39:50.160666Z"}],"euvd":[{"id":"EUVD-2026-109820","description":"Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to smuggle a second request past a front-end proxy via a chunk extension that contains a bare LF.\n\nThe chunked reader in lib/bandit/http1/socket.ex takes the chunk-size line to be everything up to the first CRLF and discards everything after ; without checking it against the RFC 9112 chunk-ext grammar, so bare LF, bare CR and other control bytes pass. A proxy that ends the size line at a bare LF reads 2;\\nxx\\r\\n40\\r\\n... as one request whose second chunk holds a GET /admin, while Bandit ends the body early and dispatches GET /admin as a separate pipelined request. Deployments without such a proxy in front of Bandit are not affected.\n\nThis issue affects bandit: from 1.12.4 before 1.14.0.","status":"published","published":"2026-10-26T13:30:41Z","modified":"2026-10-26T15:35:51Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"updated_at":"2026-11-02T16:59:29.561971Z"}],"nvd":[{"id":"CVE-2026-114216","description":"Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to smuggle a second request past a front-end proxy via a chunk extension that contains a bare LF.\n\nThe chunked reader in lib/bandit/http1/socket.ex takes the chunk-size line to be everything up to the first CRLF and discards everything after ; without checking it against the RFC 9112 chunk-ext grammar, so bare LF, bare CR and other control bytes pass. A proxy that ends the size line at a bare LF reads 2;\\nxx\\r\\n40\\r\\n... as one request whose second chunk holds a GET /admin, while Bandit ends the body early and dispatches GET /admin as a separate pipelined request. Deployments without such a proxy in front of Bandit are not affected.\n\nThis issue affects bandit: from 1.12.4 before 1.14.0.","status":"published","published":"2026-10-26T14:16:29.613Z","modified":"2026-10-26T16:59:16.113Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"}],"cwes":["CWE-444"],"updated_at":"2026-11-02T14:13:03.452847Z"}],"osv":[{"id":"CVE-2026-114216","title":"Chunk extensions accept bare LF and CR, enabling request smuggling in Bandit","description":"Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to smuggle a second request past a front-end proxy via a chunk extension that contains a bare LF.\n\nThe chunked reader in lib/bandit/http1/socket.ex takes the chunk-size line to be everything up to the first CRLF and discards everything after ; without checking it against the RFC 9112 chunk-ext grammar, so bare LF, bare CR and other control bytes pass. A proxy that ends the size line at a bare LF reads 2;\\nxx\\r\\n40\\r\\n... as one request whose second chunk holds a GET /admin, while Bandit ends the body early and dispatches GET /admin as a separate pipelined request. Deployments without such a proxy in front of Bandit are not affected.\n\nThis issue affects bandit: from 1.12.4 before 1.14.0.","status":"published","published":"2026-10-26T13:30:41.225Z","modified":"2026-10-28T02:52:21.057969477Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"cwes":["CWE-444"],"updated_at":"2026-11-02T15:44:56.310988Z"},{"id":"EEF-CVE-2026-114216","title":"Chunk extensions accept bare LF and CR, enabling request smuggling in Bandit","description":"## Summary\n\nInconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to smuggle a second request past a front-end proxy via a chunk extension that contains a bare LF.\n\nThe chunked reader in `lib/bandit/http1/socket.ex` takes the chunk-size line to be everything up to the first CRLF and discards everything after `;` without checking it against the RFC 9112 `chunk-ext` grammar, so bare LF, bare CR and other control bytes pass. A proxy that ends the size line at a bare LF reads `2;\\nxx\\r\\n40\\r\\n...` as one request whose second chunk holds a `GET /admin`, while Bandit ends the body early and dispatches `GET /admin` as a separate pipelined request. Deployments without such a proxy in front of Bandit are not affected.\n\nThis issue affects bandit: from 1.12.4 before 1.14.0.\n\n## Details\n\n**1. Unchecked extension.** In `lib/bandit/http1/socket.ex`, the chunked body reader takes the chunk-size line to be everything up to the first CRLF. Anything after `;` is thrown away without being checked against the RFC 9112 §7.1.1 `chunk-ext` grammar, so bare LF, bare CR and other control bytes are accepted. The 16-byte size-line cap does not help, because the payload needs only 5 bytes.\n\n**2. Bandit's reading.** For the body `2;\\nxx\\r\\n40\\r\\n0\\r\\n\\r\\nGET /admin ...`, Bandit takes `2;\\nxx` as the size line and `40` as the 2-byte chunk, and the embedded `0\\r\\n\\r\\n` ends the body. Bandit then runs `GET /admin` as a second pipelined request.\n\n**3. The proxy's reading.** A proxy that ends the size line at the bare LF sees only one POST, with the chunk `xx` and a 0x40-byte chunk that holds the `GET /admin` bytes.\n\n## Proof of concept\n\n1. Run Bandit with a Plug that reads the body and records each request's method and path.\n2. On one connection, send `POST /public` with `Transfer-Encoding: chunked` and the body `2;\\nxx\\r\\n40\\r\\n0\\r\\n\\r\\n`, followed directly by `GET /admin HTTP/1.1` with `Content-Length: 7` and the body `\\r\\n0\\r\\n\\r\\n`.\n3. Bandit dispatches both `POST /public` with the body `40` and `GET /admin`. A proxy that ends lines at a bare LF would have forwarded the same bytes as the single `POST /public`.\n\n## Impact\n\nBehind a front-end proxy that treats a bare LF as a line ending and forwards chunked bodies unchanged, an unauthenticated attacker can have Bandit run requests the proxy never saw, getting past the proxy's access controls.\n\n## Workarounds\n\nWhere the front-end proxy can reach Bandit over HTTP/2, disable HTTP/1 with `http_1_options: [enabled: false]`, so that the chunked body reader never runs.","status":"published","published":"2026-10-26T13:30:41.225Z","modified":"2026-10-26T13:56:06.651337148Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"cwes":["CWE-444"],"updated_at":"2026-11-02T15:46:33.047032Z"},{"id":"UBUNTU-CVE-2026-114216","description":"Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to smuggle a second request past a front-end proxy via a chunk extension that contains a bare LF. The chunked reader in lib/bandit/http1/socket.ex takes the chunk-size line to be everything up to the first CRLF and discards everything after ; without checking it against the RFC 9112 chunk-ext grammar, so bare LF, bare CR and other control bytes pass. A proxy that ends the size line at a bare LF reads 2;\\nxx\\r\\n40\\r\\n... as one request whose second chunk holds a GET /admin, while Bandit ends the body early and dispatches GET /admin as a separate pipelined request. Deployments without such a proxy in front of Bandit are not affected. This issue affects bandit: from 1.12.4 before 1.14.0.","status":"published","published":"2026-10-26T14:16:00Z","modified":"2026-10-28T20:17:45.512411907Z","cvss":[{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium"},{"version":"4.0","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"updated_at":"2026-11-02T16:55:59.591851Z"}]}}