{"id":"CVE-2026-48861","aliases":["EEF-CVE-2026-48861","EUVD-2026-33938","GHSA-2pg6-44cx-c49v"],"status":"published","title":"CRLF injection in HTTP/1 request line via unvalidated method in Mint","description":"Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in elixir-mint Mint allows HTTP Request Splitting and HTTP Request Smuggling.\n\nIn lib/mint/http1/request.ex, the encode_request_line/2 function splices the caller-supplied method and target arguments directly into the HTTP/1 request line without any character validation: [method, ?\\s, target, \" HTTP/1.1\\r\\n\"]. An application that forwards attacker-controlled input as the HTTP method or target to Mint.HTTP.request/5 is therefore exposed to request-line CRLF injection: the attacker can terminate the request line early, inject arbitrary headers, and smuggle an entirely separate pipelined HTTP request onto the same TCP connection.\n\nMint 1.7.0 introduced validate_request_target/2, which rejects CRLF and other control characters in the target by default and closes the path/query vector unless the caller opts out via skip_target_validation: true. The method field remains unvalidated, so the method-based injection is exploitable under the default Mint configuration on all versions.\n\nThis issue affects mint: from 0.1.0 before 1.9.0.","severity":{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00167,"percentile":0.06022,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-93"],"published":"2026-06-02T14:15:09Z","modified":"2026-10-28T02:31:01Z","fixes":[{"ecosystem":"Hex","package":"mint","fixed_in":["1.9.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Hex","package":"mint","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.0"}]}]},{"source":"osv","ecosystem":"Hex","package":"mint","ranges":[{"type":"SEMVER","events":[{"introduced":"0.1.0"},{"fixed":"1.9.0"}]}],"versions":["0.1.0","0.2.0","0.2.1","0.3.0","0.4.0","0.5.0","1.0.0","1.1.0","1.2.0","1.2.1","1.3.0","1.4.0","1.4.1","1.4.2","1.5.0","1.5.1","1.5.2","1.6.0","1.6.1","1.6.2","1.7.0","1.7.1","1.8.0"]},{"source":"osv","ecosystem":"Hex","package":"mint","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.9.0"}]}],"versions":["0.1.0","0.2.0","0.2.1","0.3.0","0.4.0","0.5.0","1.0.0","1.1.0","1.2.0","1.2.1","1.3.0","1.4.0","1.4.1","1.4.2","1.5.0","1.5.1","1.5.2","1.6.0","1.6.1","1.6.2","1.7.0","1.7.1","1.8.0"]}],"products":[{"vendor":"elixir-mint","product":"mint"},{"vendor":"linuxmint","product":"mint"}],"references":[{"url":"https://github.com/elixir-mint/mint/security/advisories/GHSA-2pg6-44cx-c49v","tags":["vendor-advisory","related","exploit","advisory","web"]},{"url":"https://cna.erlef.org/cves/CVE-2026-48861.html","tags":["related","web"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-48861","tags":["related","web"]},{"url":"https://github.com/elixir-mint/mint/commit/fad091454cbb7449b19edb8e1fee12ca7cf28c3a","tags":["patch","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48861","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-2pg6-44cx-c49v"},{"url":"https://github.com","tags":["web"]},{"url":"https://repo.hex.pm","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48861.json","tags":["advisory"]},{"url":"https://github.com/elixir-mint/mint","tags":["package"]},{"url":"https://github.com/elixir-mint/mint.git","tags":["package"]},{"url":"https://hex.pm/packages/mint","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-48861","title":"CRLF injection in HTTP/1 request line via unvalidated method in Mint","description":"Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in elixir-mint Mint allows HTTP Request Splitting and HTTP Request Smuggling.\n\nIn lib/mint/http1/request.ex, the encode_request_line/2 function splices the caller-supplied method and target arguments directly into the HTTP/1 request line without any character validation: [method, ?\\s, target, \" HTTP/1.1\\r\\n\"]. An application that forwards attacker-controlled input as the HTTP method or target to Mint.HTTP.request/5 is therefore exposed to request-line CRLF injection: the attacker can terminate the request line early, inject arbitrary headers, and smuggle an entirely separate pipelined HTTP request onto the same TCP connection.\n\nMint 1.7.0 introduced validate_request_target/2, which rejects CRLF and other control characters in the target by default and closes the path/query vector unless the caller opts out via skip_target_validation: true. The method field remains unvalidated, so the method-based injection is exploitable under the default Mint configuration on all versions.\n\nThis issue affects mint: from 0.1.0 before 1.9.0.","status":"published","published":"2026-06-02T14:15:09.015Z","modified":"2026-06-02T19:14:00.466Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","level":"low","assessor":"cna"}],"cwes":["CWE-93"],"updated_at":"2026-11-02T13:50:49.872037Z"}],"euvd":[{"id":"EUVD-2026-33938","description":"Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in elixir-mint Mint allows HTTP Request Splitting and HTTP Request Smuggling.\n\nIn lib/mint/http1/request.ex, the encode_request_line/2 function splices the caller-supplied method and target arguments directly into the HTTP/1 request line without any character validation: [method, ?\\s, target, \" HTTP/1.1\\r\\n\"]. An application that forwards attacker-controlled input as the HTTP method or target to Mint.HTTP.request/5 is therefore exposed to request-line CRLF injection: the attacker can terminate the request line early, inject arbitrary headers, and smuggle an entirely separate pipelined HTTP request onto the same TCP connection.\n\nMint 1.7.0 introduced validate_request_target/2, which rejects CRLF and other control characters in the target by default and closes the path/query vector unless the caller opts out via skip_target_validation: true. The method field remains unvalidated, so the method-based injection is exploitable under the default Mint configuration on all versions.\n\nThis issue affects mint: from 0.1.0 before 1.9.0.","status":"published","published":"2026-06-02T14:15:09Z","modified":"2026-06-02T19:14:00Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","level":"low"}],"updated_at":"2026-11-02T18:20:55.651138Z"}],"ghsa":[{"id":"GHSA-2pg6-44cx-c49v","title":"mint has potential CRLF injection in its HTTP request line via unvalidated `method`/`target`","description":"### Summary\n\nMint's HTTP/1 request encoder splices the caller-supplied `method` and `target` directly into the request line without character validation. An application that forwards attacker-controlled input as the HTTP method or the target to `Mint.HTTP.request/5` is exposed to request-line CRLF injection, allowing the attacker to terminate the request line early, inject arbitrary headers, and pipeline a fully attacker-chosen second request onto the same TCP connection.\n\n### Details\n\n`encode_request_line/2` in `lib/mint/http1/request.ex` writes `method` and `target` to the wire verbatim. `encode_headers/1` validates header names and values, but there is no equivalent `validate_method!/1`.\n\nMint 1.7.0 added `validate_request_target/2`, which rejects CRLF and other control characters in `target` by default and closes the path/query vector. The `method` field remains unvalidated, so a CRLF-bearing method such as `\"GET / HTTP/1.1\\r\\nX-Smuggled: 1\\r\\nGET /admin\"` is accepted and written to the socket as-is. Bytes after the first `\\r\\n` are interpreted by the peer as an injected header, or, with a second `\\r\\n`, as an additional pipelined request.\n\n### PoC\n\n1. Stand up a Mint-using gateway/proxy that calls `Mint.HTTP.request(conn, method, \"/\", [], nil)` with `method` taken from caller input.\n2. Send a request whose forwarded method is `\"GET / HTTP/1.1\\r\\nX-Smuggled-Header: pwned\\r\\nGET /admin/delete-everything\"`.\n3. Observe the bytes received by the upstream server: the smuggled header line and the second request line appear verbatim in the outbound stream.\n\n### Impact\n\nCRLF injection / HTTP request smuggling in the HTTP/1 client encoder, exploitable under default configuration whenever an application passes caller-influenced input as the HTTP method. An attacker who controls the method can inject arbitrary outbound headers (forged `Host`, `Authorization`, cache-poisoning headers) and smuggle additional, fully attacker-chosen requests to the upstream server over the same connection, potentially reaching endpoints the legitimate caller never intended to invoke.\n\n## Resources\n\n* Introduction commit: https://github.com/elixir-mint/mint/commit/8db1acff30b6a9433762c18b1e1f891b8c1f74f7\n* Patch commit: https://github.com/elixir-mint/mint/commit/fad091454cbb7449b19edb8e1fee12ca7cf28c3a","status":"published","published":"2026-07-09T23:19:12Z","modified":"2026-07-09T23:19:12Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","level":"low"}],"cwes":["CWE-93"],"updated_at":"2026-11-02T14:40:41.501474Z"}],"nvd":[{"id":"CVE-2026-48861","description":"Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in elixir-mint Mint allows HTTP Request Splitting and HTTP Request Smuggling.\n\nIn lib/mint/http1/request.ex, the encode_request_line/2 function splices the caller-supplied method and target arguments directly into the HTTP/1 request line without any character validation: [method, ?\\s, target, \" HTTP/1.1\\r\\n\"]. An application that forwards attacker-controlled input as the HTTP method or target to Mint.HTTP.request/5 is therefore exposed to request-line CRLF injection: the attacker can terminate the request line early, inject arbitrary headers, and smuggle an entirely separate pipelined HTTP request onto the same TCP connection.\n\nMint 1.7.0 introduced validate_request_target/2, which rejects CRLF and other control characters in the target by default and closes the path/query vector unless the caller opts out via skip_target_validation: true. The method field remains unvalidated, so the method-based injection is exploitable under the default Mint configuration on all versions.\n\nThis issue affects mint: from 0.1.0 before 1.9.0.","status":"published","published":"2026-06-02T16:16:44.47Z","modified":"2026-07-22T19:10:00.12Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/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":"low","assessor":"secondary"}],"cwes":["CWE-93"],"updated_at":"2026-11-02T14:12:22.022466Z"}],"osv":[{"id":"CVE-2026-48861","title":"CRLF injection in HTTP/1 request line via unvalidated method in Mint","description":"Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in elixir-mint Mint allows HTTP Request Splitting and HTTP Request Smuggling.\n\nIn lib/mint/http1/request.ex, the encode_request_line/2 function splices the caller-supplied method and target arguments directly into the HTTP/1 request line without any character validation: [method, ?\\s, target, \" HTTP/1.1\\r\\n\"]. An application that forwards attacker-controlled input as the HTTP method or target to Mint.HTTP.request/5 is therefore exposed to request-line CRLF injection: the attacker can terminate the request line early, inject arbitrary headers, and smuggle an entirely separate pipelined HTTP request onto the same TCP connection.\n\nMint 1.7.0 introduced validate_request_target/2, which rejects CRLF and other control characters in the target by default and closes the path/query vector unless the caller opts out via skip_target_validation: true. The method field remains unvalidated, so the method-based injection is exploitable under the default Mint configuration on all versions.\n\nThis issue affects mint: from 0.1.0 before 1.9.0.","status":"published","published":"2026-06-02T14:15:09.015Z","modified":"2026-10-28T02:31:01.953762357Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","level":"low"}],"cwes":["CWE-93"],"updated_at":"2026-11-02T15:45:07.060148Z"},{"id":"EEF-CVE-2026-48861","title":"CRLF injection in HTTP/1 request line via unvalidated method in Mint","description":"## Summary\n\nImproper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in elixir-mint Mint allows HTTP Request Splitting and HTTP Request Smuggling.\n\nIn lib/mint/http1/request.ex, the encode\\_request\\_line/2 function splices the caller-supplied method and target arguments directly into the HTTP/1 request line without any character validation: \\[method, ?\\\\s, target, \" HTTP/1.1\\\\r\\\\n\"\\]. An application that forwards attacker-controlled input as the HTTP method or target to Mint.HTTP.request/5 is therefore exposed to request-line CRLF injection: the attacker can terminate the request line early, inject arbitrary headers, and smuggle an entirely separate pipelined HTTP request onto the same TCP connection.\n\nMint 1.7.0 introduced validate\\_request\\_target/2, which rejects CRLF and other control characters in the target by default and closes the path/query vector unless the caller opts out via skip\\_target\\_validation: true. The method field remains unvalidated, so the method-based injection is exploitable under the default Mint configuration on all versions.\n\nThis issue affects mint: from 0.1.0 before 1.9.0.","status":"published","published":"2026-06-02T14:15:09.015Z","modified":"2026-07-30T18:22:01.594144Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","level":"low"}],"cwes":["CWE-93"],"updated_at":"2026-11-02T15:46:33.520522Z"},{"id":"GHSA-2pg6-44cx-c49v","title":"mint has potential CRLF injection in its HTTP request line via unvalidated `method`/`target`","description":"### Summary\n\nMint's HTTP/1 request encoder splices the caller-supplied `method` and `target` directly into the request line without character validation. An application that forwards attacker-controlled input as the HTTP method or the target to `Mint.HTTP.request/5` is exposed to request-line CRLF injection, allowing the attacker to terminate the request line early, inject arbitrary headers, and pipeline a fully attacker-chosen second request onto the same TCP connection.\n\n### Details\n\n`encode_request_line/2` in `lib/mint/http1/request.ex` writes `method` and `target` to the wire verbatim. `encode_headers/1` validates header names and values, but there is no equivalent `validate_method!/1`.\n\nMint 1.7.0 added `validate_request_target/2`, which rejects CRLF and other control characters in `target` by default and closes the path/query vector. The `method` field remains unvalidated, so a CRLF-bearing method such as `\"GET / HTTP/1.1\\r\\nX-Smuggled: 1\\r\\nGET /admin\"` is accepted and written to the socket as-is. Bytes after the first `\\r\\n` are interpreted by the peer as an injected header, or, with a second `\\r\\n`, as an additional pipelined request.\n\n### PoC\n\n1. Stand up a Mint-using gateway/proxy that calls `Mint.HTTP.request(conn, method, \"/\", [], nil)` with `method` taken from caller input.\n2. Send a request whose forwarded method is `\"GET / HTTP/1.1\\r\\nX-Smuggled-Header: pwned\\r\\nGET /admin/delete-everything\"`.\n3. Observe the bytes received by the upstream server: the smuggled header line and the second request line appear verbatim in the outbound stream.\n\n### Impact\n\nCRLF injection / HTTP request smuggling in the HTTP/1 client encoder, exploitable under default configuration whenever an application passes caller-influenced input as the HTTP method. An attacker who controls the method can inject arbitrary outbound headers (forged `Host`, `Authorization`, cache-poisoning headers) and smuggle additional, fully attacker-chosen requests to the upstream server over the same connection, potentially reaching endpoints the legitimate caller never intended to invoke.\n\n## Resources\n\n* Introduction commit: https://github.com/elixir-mint/mint/commit/8db1acff30b6a9433762c18b1e1f891b8c1f74f7\n* Patch commit: https://github.com/elixir-mint/mint/commit/fad091454cbb7449b19edb8e1fee12ca7cf28c3a","status":"published","published":"2026-07-09T23:19:12Z","modified":"2026-07-09T23:30:10.333707326Z","cvss":[{"version":"4.0","score":2.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","level":"low"}],"cwes":["CWE-93"],"updated_at":"2026-11-02T15:46:34.700741Z"}]}}