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              "value": "\u003cp\u003eImproper Neutralization of CRLF Sequences in HTTP Headers (\u0027HTTP Request/Response Splitting\u0027) vulnerability in \u003ccode\u003ehackney_http_connect\u003c/code\u003e in benoitc hackney allows HTTP Request Splitting via the value a \u003ccode\u003eproxy_auth_fun\u003c/code\u003e callback returns. After a 407 response from an HTTP CONNECT proxy, \u003ccode\u003ehackney_http_connect:handle_proxy_auth/11\u003c/code\u003e calls the caller\u0027s \u003ccode\u003eproxy_auth_fun\u003c/code\u003e with the status code and the response headers and writes the returned binary into the \u003ccode\u003eProxy-Authorization\u003c/code\u003e line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.\u003c/p\u003e\n\u003cp\u003eThe value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy\u0027s challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.\u003c/p\u003e\n\u003cp\u003eThis issue affects hackney: from 2.0.0 before 4.9.0.\u003c/p\u003e"
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              "value": "Improper Neutralization of CRLF Sequences in HTTP Headers (\u0027HTTP Request/Response Splitting\u0027) vulnerability in `hackney_http_connect` in benoitc hackney allows HTTP Request Splitting via the value a `proxy_auth_fun` callback returns. After a 407 response from an HTTP CONNECT proxy, `hackney_http_connect:handle_proxy_auth/11` calls the caller\u0027s `proxy_auth_fun` with the status code and the response headers and writes the returned binary into the `Proxy-Authorization` line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.\n\nThe value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy\u0027s challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.\n\nThis issue affects hackney: from 2.0.0 before 4.9.0."
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      "title": "CRLF injection in Proxy-Authorization header built from proxy_auth_fun in hackney",
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              "value": "\u003cp\u003eCheck the value your \u003ccode\u003eproxy_auth_fun\u003c/code\u003e is about to return for CR, LF and NUL bytes and return \u003ccode\u003e{error, Reason}\u003c/code\u003e instead when one is present. The callback runs in the application, so the check can be made there.\u003c/p\u003e"
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              "value": "Check the value your `proxy_auth_fun` is about to return for CR, LF and NUL bytes and return `{error, Reason}` instead when one is present. The callback runs in the application, so the check can be made there."
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              "value": "\u003cp\u003e\u003cstrong\u003e1. Challenge.\u003c/strong\u003e \u003ccode\u003ehackney_http_connect:do_handshake_with_auth/9\u003c/code\u003e in \u003ccode\u003esrc/hackney_http_connect.erl\u003c/code\u003e sends the CONNECT request to the proxy. When the proxy answers 407 and the \u003ccode\u003eproxy_auth_fun\u003c/code\u003e option is set, it hands the status code and the parsed response headers to \u003ccode\u003ehackney_http_connect:handle_proxy_auth/11\u003c/code\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2. Callback result.\u003c/strong\u003e \u003ccode\u003ehandle_proxy_auth/11\u003c/code\u003e calls the caller\u0027s \u003ccode\u003eproxy_auth_fun\u003c/code\u003e with those two values. On \u003ccode\u003e{ok, AuthHeader}\u003c/code\u003e it removes any existing \u003ccode\u003eProxy-Authorization\u003c/code\u003e header and appends the binary \u003ccode\u003e\u0026lt;\u0026lt;\"Proxy-Authorization: \", AuthHeader/binary\u0026gt;\u0026gt;\u003c/code\u003e to the header list, then retries the handshake with it.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3. Splitting.\u003c/strong\u003e The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside \u003ccode\u003eAuthHeader\u003c/code\u003e therefore ends the \u003ccode\u003eProxy-Authorization\u003c/code\u003e line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same \u003ccode\u003ehas_ctl_bytes/1\u003c/code\u003e check to it and returns \u003ccode\u003e{error, {proxy_auth_error, invalid_header}}\u003c/code\u003e.\u003c/p\u003e"
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              "value": "**1. Challenge.** `hackney_http_connect:do_handshake_with_auth/9` in `src/hackney_http_connect.erl` sends the CONNECT request to the proxy. When the proxy answers 407 and the `proxy_auth_fun` option is set, it hands the status code and the parsed response headers to `hackney_http_connect:handle_proxy_auth/11`.\n\n**2. Callback result.** `handle_proxy_auth/11` calls the caller\u0027s `proxy_auth_fun` with those two values. On `{ok, AuthHeader}` it removes any existing `Proxy-Authorization` header and appends the binary `\u003c\u003c\"Proxy-Authorization: \", AuthHeader/binary\u003e\u003e` to the header list, then retries the handshake with it.\n\n**3. Splitting.** The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside `AuthHeader` therefore ends the `Proxy-Authorization` line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same `has_ctl_bytes/1` check to it and returns `{error, {proxy_auth_error, invalid_header}}`."
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          "value": "1. Challenge. hackney_http_connect:do_handshake_with_auth/9 in src/hackney_http_connect.erl sends the CONNECT request to the proxy. When the proxy answers 407 and the proxy_auth_fun option is set, it hands the status code and the parsed response headers to hackney_http_connect:handle_proxy_auth/11.\n\n2. Callback result. handle_proxy_auth/11 calls the caller\u0027s proxy_auth_fun with those two values. On {ok, AuthHeader} it removes any existing Proxy-Authorization header and appends the binary \u003c\u003c\"Proxy-Authorization: \", AuthHeader/binary\u003e\u003e to the header list, then retries the handshake with it.\n\n3. Splitting. The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside AuthHeader therefore ends the Proxy-Authorization line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same has_ctl_bytes/1 check to it and returns {error, {proxy_auth_error, invalid_header}}."
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\"vendor\": \"benoitc\", \"modules\": [\"hackney_http_connect\"], \"product\": \"hackney\", \"versions\": [{\"status\": \"affected\", \"version\": \"2.0.0\", \"lessThan\": \"4.9.0\", \"versionType\": \"semver\"}], \"packageURL\": \"pkg:hex/hackney\", \"packageName\": \"hackney\", \"programFiles\": [\"src/hackney_http_connect.erl\"], \"collectionURL\": \"https://repo.hex.pm\", \"defaultStatus\": \"unaffected\", \"programRoutines\": [{\"name\": \"hackney_http_connect:connect/4\"}, {\"name\": \"hackney_http_connect:do_handshake_with_auth/9\"}, {\"name\": \"hackney_http_connect:handle_proxy_auth/11\"}]}, {\"cpes\": [\"cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*\"], \"repo\": \"https://github.com/benoitc/hackney\", \"vendor\": \"benoitc\", \"modules\": [\"hackney_http_connect\"], \"product\": \"hackney\", \"versions\": [{\"status\": \"affected\", \"version\": \"5df5a74a2817d5b12880d217db33253ff1fae1b5\", \"lessThan\": \"5ee7d7d19eba27e774667d472feb1e93a08af7f9\", \"versionType\": \"git\"}], \"packageURL\": \"pkg:github/benoitc/hackney\", \"packageName\": \"benoitc/hackney\", \"programFiles\": [\"src/hackney_http_connect.erl\"], \"collectionURL\": \"https://github.com\", \"defaultStatus\": \"unaffected\", \"programRoutines\": [{\"name\": \"hackney_http_connect:connect/4\"}, {\"name\": \"hackney_http_connect:do_handshake_with_auth/9\"}, {\"name\": \"hackney_http_connect:handle_proxy_auth/11\"}]}], \"datePublic\": \"2026-10-25T00:00:00.000Z\", \"references\": [{\"url\": \"https://github.com/benoitc/hackney/releases/tag/4.9.0\", \"name\": \"hackney 4.9.0 release notes\", \"tags\": [\"vendor-advisory\", \"related\"]}, {\"url\": \"https://cna.erlef.org/cves/CVE-2026-112880.html\", \"name\": \"EEF CNA record for CVE-2026-112880\", \"tags\": [\"related\"]}, {\"url\": \"https://osv.dev/vulnerability/EEF-CVE-2026-112880\", \"name\": \"OSV record EEF-CVE-2026-112880\", \"tags\": [\"related\"]}, {\"url\": \"https://github.com/benoitc/hackney/pull/989\", \"name\": \"Refuse CR/LF/NUL in the proxy_auth_fun result (benoitc/hackney#989)\", \"tags\": [\"related\"]}, {\"url\": \"https://github.com/benoitc/hackney/commit/5df5a74a2817d5b12880d217db33253ff1fae1b5\", \"name\": \"Introducing commit 5df5a74 in benoitc/hackney\", \"tags\": [\"related\"]}, {\"url\": \"https://github.com/benoitc/hackney/commit/5ee7d7d19eba27e774667d472feb1e93a08af7f9\", \"name\": \"Fix commit 5ee7d7d in benoitc/hackney\", \"tags\": [\"patch\"]}], \"workarounds\": [{\"lang\": \"en\", \"value\": \"Check the value your proxy_auth_fun is about to return for CR, LF and NUL bytes and return {error, Reason} instead when one is present. The callback runs in the application, so the check can be made there.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003eCheck the value your \u003ccode\u003eproxy_auth_fun\u003c/code\u003e is about to return for CR, LF and NUL bytes and return \u003ccode\u003e{error, Reason}\u003c/code\u003e instead when one is present. The callback runs in the application, so the check can be made there.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"Check the value your `proxy_auth_fun` is about to return for CR, LF and NUL bytes and return `{error, Reason}` instead when one is present. The callback runs in the application, so the check can be made there.\", \"base64\": false}]}], \"dateAssigned\": \"2026-10-26T10:18:44.000Z\", \"descriptions\": [{\"lang\": \"en\", \"value\": \"Improper Neutralization of CRLF Sequences in HTTP Headers (\u0027HTTP Request/Response Splitting\u0027) vulnerability in hackney_http_connect in benoitc hackney allows HTTP Request Splitting via the value a proxy_auth_fun callback returns. After a 407 response from an HTTP CONNECT proxy, hackney_http_connect:handle_proxy_auth/11 calls the caller\u0027s proxy_auth_fun with the status code and the response headers and writes the returned binary into the Proxy-Authorization line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.\\n\\nThe value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy\u0027s challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.\\n\\nThis issue affects hackney: from 2.0.0 before 4.9.0.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003eImproper Neutralization of CRLF Sequences in HTTP Headers (\u0027HTTP Request/Response Splitting\u0027) vulnerability in \u003ccode\u003ehackney_http_connect\u003c/code\u003e in benoitc hackney allows HTTP Request Splitting via the value a \u003ccode\u003eproxy_auth_fun\u003c/code\u003e callback returns. After a 407 response from an HTTP CONNECT proxy, \u003ccode\u003ehackney_http_connect:handle_proxy_auth/11\u003c/code\u003e calls the caller\u0027s \u003ccode\u003eproxy_auth_fun\u003c/code\u003e with the status code and the response headers and writes the returned binary into the \u003ccode\u003eProxy-Authorization\u003c/code\u003e line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.\u003c/p\u003e\\n\u003cp\u003eThe value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy\u0027s challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.\u003c/p\u003e\\n\u003cp\u003eThis issue affects hackney: from 2.0.0 before 4.9.0.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"Improper Neutralization of CRLF Sequences in HTTP Headers (\u0027HTTP Request/Response Splitting\u0027) vulnerability in `hackney_http_connect` in benoitc hackney allows HTTP Request Splitting via the value a `proxy_auth_fun` callback returns. After a 407 response from an HTTP CONNECT proxy, `hackney_http_connect:handle_proxy_auth/11` calls the caller\u0027s `proxy_auth_fun` with the status code and the response headers and writes the returned binary into the `Proxy-Authorization` line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.\\n\\nThe value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy\u0027s challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.\\n\\nThis issue affects hackney: from 2.0.0 before 4.9.0.\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-113\", \"description\": \"CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers (\u0027HTTP Request/Response Splitting\u0027)\"}]}], \"configurations\": [{\"lang\": \"en\", \"value\": \"The client connects through an HTTP CONNECT proxy with the proxy_auth_fun option set, and the callback builds its result from data an untrusted party can influence, such as the proxy\u0027s 407 challenge headers. Deployments without proxy_auth_fun, or whose callback returns a fixed credential, are not affected.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003eThe client connects through an HTTP CONNECT proxy with the \u003ccode\u003eproxy_auth_fun\u003c/code\u003e option set, and the callback builds its result from data an untrusted party can influence, such as the proxy\u0027s 407 challenge headers. Deployments without \u003ccode\u003eproxy_auth_fun\u003c/code\u003e, or whose callback returns a fixed credential, are not affected.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"The client connects through an HTTP CONNECT proxy with the `proxy_auth_fun` option set, and the callback builds its result from data an untrusted party can influence, such as the proxy\u0027s 407 challenge headers. Deployments without `proxy_auth_fun`, or whose callback returns a fixed credential, are not affected.\", \"base64\": false}]}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"4.9.0\", \"versionStartIncluding\": \"2.0.0\"}], \"operator\": \"OR\"}], \"operator\": \"AND\"}], \"providerMetadata\": {\"orgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"shortName\": \"EEF\", \"dateUpdated\": \"2026-10-26T13:48:46.589Z\"}, \"x_technicalAnalysis\": [{\"lang\": \"en\", \"value\": \"1. Challenge. hackney_http_connect:do_handshake_with_auth/9 in src/hackney_http_connect.erl sends the CONNECT request to the proxy. When the proxy answers 407 and the proxy_auth_fun option is set, it hands the status code and the parsed response headers to hackney_http_connect:handle_proxy_auth/11.\\n\\n2. Callback result. handle_proxy_auth/11 calls the caller\u0027s proxy_auth_fun with those two values. On {ok, AuthHeader} it removes any existing Proxy-Authorization header and appends the binary \u003c\u003c\\\"Proxy-Authorization: \\\", AuthHeader/binary\u003e\u003e to the header list, then retries the handshake with it.\\n\\n3. Splitting. The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside AuthHeader therefore ends the Proxy-Authorization line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same has_ctl_bytes/1 check to it and returns {error, {proxy_auth_error, invalid_header}}.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003e\u003cstrong\u003e1. Challenge.\u003c/strong\u003e \u003ccode\u003ehackney_http_connect:do_handshake_with_auth/9\u003c/code\u003e in \u003ccode\u003esrc/hackney_http_connect.erl\u003c/code\u003e sends the CONNECT request to the proxy. When the proxy answers 407 and the \u003ccode\u003eproxy_auth_fun\u003c/code\u003e option is set, it hands the status code and the parsed response headers to \u003ccode\u003ehackney_http_connect:handle_proxy_auth/11\u003c/code\u003e.\u003c/p\u003e\\n\u003cp\u003e\u003cstrong\u003e2. Callback result.\u003c/strong\u003e \u003ccode\u003ehandle_proxy_auth/11\u003c/code\u003e calls the caller\u0027s \u003ccode\u003eproxy_auth_fun\u003c/code\u003e with those two values. On \u003ccode\u003e{ok, AuthHeader}\u003c/code\u003e it removes any existing \u003ccode\u003eProxy-Authorization\u003c/code\u003e header and appends the binary \u003ccode\u003e\u0026lt;\u0026lt;\\\"Proxy-Authorization: \\\", AuthHeader/binary\u0026gt;\u0026gt;\u003c/code\u003e to the header list, then retries the handshake with it.\u003c/p\u003e\\n\u003cp\u003e\u003cstrong\u003e3. Splitting.\u003c/strong\u003e The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside \u003ccode\u003eAuthHeader\u003c/code\u003e therefore ends the \u003ccode\u003eProxy-Authorization\u003c/code\u003e line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same \u003ccode\u003ehas_ctl_bytes/1\u003c/code\u003e check to it and returns \u003ccode\u003e{error, {proxy_auth_error, invalid_header}}\u003c/code\u003e.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"**1. Challenge.** `hackney_http_connect:do_handshake_with_auth/9` in `src/hackney_http_connect.erl` sends the CONNECT request to the proxy. When the proxy answers 407 and the `proxy_auth_fun` option is set, it hands the status code and the parsed response headers to `hackney_http_connect:handle_proxy_auth/11`.\\n\\n**2. Callback result.** `handle_proxy_auth/11` calls the caller\u0027s `proxy_auth_fun` with those two values. On `{ok, AuthHeader}` it removes any existing `Proxy-Authorization` header and appends the binary `\u003c\u003c\\\"Proxy-Authorization: \\\", AuthHeader/binary\u003e\u003e` to the header list, then retries the handshake with it.\\n\\n**3. Splitting.** The header list is joined with CRLF into the CONNECT request. A CR, LF or NUL byte inside `AuthHeader` therefore ends the `Proxy-Authorization` line early and the rest is sent as further header lines. The target host and the request headers go through control-byte checks on this path; the callback result did not. The fix applies the same `has_ctl_bytes/1` check to it and returns `{error, {proxy_auth_error, invalid_header}}`.\", \"base64\": false}]}]}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-112880\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-10-26T15:35:50.632Z\", \"dateReserved\": \"2026-10-26T10:15:01.166Z\", \"assignerOrgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"datePublished\": \"2026-10-26T13:48:46.589Z\", \"assignerShortName\": \"EEF\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}