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              "value": "\u003cp\u003eInconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027) 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.\u003c/p\u003e\n\u003cp\u003eThe chunked reader in \u003ccode\u003elib/bandit/http1/socket.ex\u003c/code\u003e takes the chunk-size line to be everything up to the first CRLF and discards everything after \u003ccode\u003e;\u003c/code\u003e without checking it against the RFC 9112 \u003ccode\u003echunk-ext\u003c/code\u003e grammar, so bare LF, bare CR and other control bytes pass. A proxy that ends the size line at a bare LF reads \u003ccode\u003e2;\\nxx\\r\\n40\\r\\n...\u003c/code\u003e as one request whose second chunk holds a \u003ccode\u003eGET /admin\u003c/code\u003e, while Bandit ends the body early and dispatches \u003ccode\u003eGET /admin\u003c/code\u003e as a separate pipelined request. Deployments without such a proxy in front of Bandit are not affected.\u003c/p\u003e\n\u003cp\u003eThis issue affects bandit: from 1.12.4 before 1.14.0.\u003c/p\u003e"
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      "title": "Chunk extensions accept bare LF and CR, enabling request smuggling in Bandit",
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              "value": "\u003cp\u003eWhere the front-end proxy can reach Bandit over HTTP/2, disable HTTP/1 with \u003ccode\u003ehttp_1_options: [enabled: false]\u003c/code\u003e, so that the chunked body reader never runs.\u003c/p\u003e"
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              "value": "Where 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."
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              "value": "\u003col\u003e\n\u003cli\u003eRun Bandit with a Plug that reads the body and records each request\u0027s method and path.\u003c/li\u003e\n\u003cli\u003eOn one connection, send \u003ccode\u003ePOST /public\u003c/code\u003e with \u003ccode\u003eTransfer-Encoding: chunked\u003c/code\u003e and the body \u003ccode\u003e2;\\nxx\\r\\n40\\r\\n0\\r\\n\\r\\n\u003c/code\u003e, followed directly by \u003ccode\u003eGET /admin HTTP/1.1\u003c/code\u003e with \u003ccode\u003eContent-Length: 7\u003c/code\u003e and the body \u003ccode\u003e\\r\\n0\\r\\n\\r\\n\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eBandit dispatches both \u003ccode\u003ePOST /public\u003c/code\u003e with the body \u003ccode\u003e40\u003c/code\u003e and \u003ccode\u003eGET /admin\u003c/code\u003e. A proxy that ends lines at a bare LF would have forwarded the same bytes as the single \u003ccode\u003ePOST /public\u003c/code\u003e.\u003c/li\u003e\n\u003c/ol\u003e"
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              "value": "1. Run Bandit with a Plug that reads the body and records each request\u0027s 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`."
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          "value": "* Run Bandit with a Plug that reads the body and records each request\u0027s method and path.\n* 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.\n* 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."
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              "value": "\u003cp\u003e\u003cstrong\u003e1. Unchecked extension.\u003c/strong\u003e In \u003ccode\u003elib/bandit/http1/socket.ex\u003c/code\u003e, the chunked body reader takes the chunk-size line to be everything up to the first CRLF. Anything after \u003ccode\u003e;\u003c/code\u003e is thrown away without being checked against the RFC 9112 \u00a77.1.1 \u003ccode\u003echunk-ext\u003c/code\u003e 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.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2. Bandit\u0027s reading.\u003c/strong\u003e For the body \u003ccode\u003e2;\\nxx\\r\\n40\\r\\n0\\r\\n\\r\\nGET /admin ...\u003c/code\u003e, Bandit takes \u003ccode\u003e2;\\nxx\u003c/code\u003e as the size line and \u003ccode\u003e40\u003c/code\u003e as the 2-byte chunk, and the embedded \u003ccode\u003e0\\r\\n\\r\\n\u003c/code\u003e ends the body. Bandit then runs \u003ccode\u003eGET /admin\u003c/code\u003e as a second pipelined request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3. The proxy\u0027s reading.\u003c/strong\u003e A proxy that ends the size line at the bare LF sees only one POST, with the chunk \u003ccode\u003exx\u003c/code\u003e and a 0x40-byte chunk that holds the \u003ccode\u003eGET /admin\u003c/code\u003e bytes.\u003c/p\u003e"
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              "value": "**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 \u00a77.1.1 `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\u0027s 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\u0027s 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."
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    "dateReserved": "2026-10-23T10:45:02.529Z",
    "dateUpdated": "2026-10-26T15:35:51.933Z",
    "state": "PUBLISHED"
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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.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003eInconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027) 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.\u003c/p\u003e\\n\u003cp\u003eThe chunked reader in \u003ccode\u003elib/bandit/http1/socket.ex\u003c/code\u003e takes the chunk-size line to be everything up to the first CRLF and discards everything after \u003ccode\u003e;\u003c/code\u003e without checking it against the RFC 9112 \u003ccode\u003echunk-ext\u003c/code\u003e grammar, so bare LF, bare CR and other control bytes pass. A proxy that ends the size line at a bare LF reads \u003ccode\u003e2;\\\\nxx\\\\r\\\\n40\\\\r\\\\n...\u003c/code\u003e as one request whose second chunk holds a \u003ccode\u003eGET /admin\u003c/code\u003e, while Bandit ends the body early and dispatches \u003ccode\u003eGET /admin\u003c/code\u003e as a separate pipelined request. Deployments without such a proxy in front of Bandit are not affected.\u003c/p\u003e\\n\u003cp\u003eThis issue affects bandit: from 1.12.4 before 1.14.0.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027) 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.\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-444\", \"description\": \"CWE-444 Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)\"}]}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"1.14.0\", \"versionStartIncluding\": \"1.12.4\"}], \"operator\": \"OR\"}], \"operator\": \"AND\"}], \"providerMetadata\": {\"orgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"shortName\": \"EEF\", \"dateUpdated\": \"2026-10-26T13:30:41.225Z\"}, \"x_proofOfConcept\": [{\"lang\": \"en\", \"value\": \"* Run Bandit with a Plug that reads the body and records each request\u0027s method and path.\\n* 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.\\n* 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.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003col\u003e\\n\u003cli\u003eRun Bandit with a Plug that reads the body and records each request\u0027s method and path.\u003c/li\u003e\\n\u003cli\u003eOn one connection, send \u003ccode\u003ePOST /public\u003c/code\u003e with \u003ccode\u003eTransfer-Encoding: chunked\u003c/code\u003e and the body \u003ccode\u003e2;\\\\nxx\\\\r\\\\n40\\\\r\\\\n0\\\\r\\\\n\\\\r\\\\n\u003c/code\u003e, followed directly by \u003ccode\u003eGET /admin HTTP/1.1\u003c/code\u003e with \u003ccode\u003eContent-Length: 7\u003c/code\u003e and the body \u003ccode\u003e\\\\r\\\\n0\\\\r\\\\n\\\\r\\\\n\u003c/code\u003e.\u003c/li\u003e\\n\u003cli\u003eBandit dispatches both \u003ccode\u003ePOST /public\u003c/code\u003e with the body \u003ccode\u003e40\u003c/code\u003e and \u003ccode\u003eGET /admin\u003c/code\u003e. A proxy that ends lines at a bare LF would have forwarded the same bytes as the single \u003ccode\u003ePOST /public\u003c/code\u003e.\u003c/li\u003e\\n\u003c/ol\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"1. Run Bandit with a Plug that reads the body and records each request\u0027s 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`.\", \"base64\": false}]}], \"x_technicalAnalysis\": [{\"lang\": \"en\", \"value\": \"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 \\u00a77.1.1 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\\n2. Bandit\u0027s 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\\n3. The proxy\u0027s 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.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003e\u003cstrong\u003e1. Unchecked extension.\u003c/strong\u003e In \u003ccode\u003elib/bandit/http1/socket.ex\u003c/code\u003e, the chunked body reader takes the chunk-size line to be everything up to the first CRLF. Anything after \u003ccode\u003e;\u003c/code\u003e is thrown away without being checked against the RFC 9112 \\u00a77.1.1 \u003ccode\u003echunk-ext\u003c/code\u003e 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.\u003c/p\u003e\\n\u003cp\u003e\u003cstrong\u003e2. Bandit\u0027s reading.\u003c/strong\u003e For the body \u003ccode\u003e2;\\\\nxx\\\\r\\\\n40\\\\r\\\\n0\\\\r\\\\n\\\\r\\\\nGET /admin ...\u003c/code\u003e, Bandit takes \u003ccode\u003e2;\\\\nxx\u003c/code\u003e as the size line and \u003ccode\u003e40\u003c/code\u003e as the 2-byte chunk, and the embedded \u003ccode\u003e0\\\\r\\\\n\\\\r\\\\n\u003c/code\u003e ends the body. Bandit then runs \u003ccode\u003eGET /admin\u003c/code\u003e as a second pipelined request.\u003c/p\u003e\\n\u003cp\u003e\u003cstrong\u003e3. The proxy\u0027s reading.\u003c/strong\u003e A proxy that ends the size line at the bare LF sees only one POST, with the chunk \u003ccode\u003exx\u003c/code\u003e and a 0x40-byte chunk that holds the \u003ccode\u003eGET /admin\u003c/code\u003e bytes.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"**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 \\u00a77.1.1 `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\u0027s 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\u0027s 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.\", \"base64\": false}]}]}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-114216\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-10-26T15:35:51.933Z\", \"dateReserved\": \"2026-10-23T10:45:02.529Z\", \"assignerOrgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"datePublished\": \"2026-10-26T13:30:41.225Z\", \"assignerShortName\": \"EEF\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}