{"id":"EEF-CVE-2026-82731","summary":"Unescaped path parameters in AshTypescript generated TypeScript client allow request redirection","details":"## Summary\n\nURL Redirection to Untrusted Site ('Open Redirect') vulnerability in ash-project ash_typescript allows an attacker who controls a path-parameter value to redirect a generated client's request, and the credentials attached to it, to an unintended route or an external origin.\n\nThe URL builders in `lib/ash_typescript/typed_controller/codegen/route_renderer.ex` replace each `:param` placeholder with a bare template interpolation and never call `encodeURIComponent`, so the value reaches `executeTypedControllerRequest` raw. A value containing `../` is normalised away by the fetch URL resolver and reaches a different route, while `?` or `#` truncates the path and can smuggle or override query parameters. For a route whose path begins with a parameter, a value such as `/evil.example.com/x` yields the protocol-relative URL `//evil.example.com/x`, sending the request and the credentials from `TypedControllerConfig` to an attacker-controlled host. Nothing constrains the value at runtime: `get_path_param_type/2` emits only a TypeScript type, which is erased.\n\nThe query-string path is unaffected, since `URLSearchParams.set` encodes its own values.\n\nThis issue affects ash_typescript: from 0.15.0 before 0.18.0.\n\n## Configurations\n\nThe application ships a TypeScript client generated by AshTypescript for a typed-controller route taking a path parameter, and passes untrusted input as that parameter.","aliases":["CVE-2026-82731","GHSA-6g23-p936-fm2f"],"modified":"2026-09-08T03:30:04.089543386Z","published":"2026-09-01T02:09:38.801Z","database_specific":{"capec_ids":["CAPEC-72"],"cpe_ids":["cpe:2.3:a:ash-project:ash_typescript:*:*:*:*:*:*:*:*"],"cwe_ids":["CWE-601"]},"references":[{"type":"ADVISORY","url":"https://github.com/ash-project/ash_typescript/security/advisories/GHSA-6g23-p936-fm2f"},{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-82731.html"},{"type":"FIX","url":"https://github.com/ash-project/ash_typescript/commit/5165f752f5f92b755d946f2d1ce750ff69083ffc"},{"type":"PACKAGE","url":"https://hex.pm/packages/ash_typescript"}],"affected":[{"package":{"name":"ash_typescript","ecosystem":"Hex","purl":"pkg:hex/ash_typescript"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.15.0"},{"fixed":"0.18.0"}]}],"versions":["0.15.0","0.15.1","0.15.2","0.15.3","0.16.0","0.17.0","0.17.1","0.17.2","0.17.3"],"database_specific":{"source":"https://cna.erlef.org/osv/EEF-CVE-2026-82731.json"}},{"ranges":[{"type":"GIT","repo":"https://github.com/ash-project/ash_typescript","events":[{"introduced":"6669e22ece34b4534e706a46d1842f01b68ee23a"},{"fixed":"5165f752f5f92b755d946f2d1ce750ff69083ffc"}]}],"versions":["v0.15.0","v0.15.3","v0.15.2","v0.15.1"],"database_specific":{"source":"https://cna.erlef.org/osv/EEF-CVE-2026-82731.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:N/SA:N"}],"credits":[{"name":"Peter Ullrich","type":"FINDER"},{"name":"Peter Ullrich","type":"REPORTER"},{"name":"Torkild Gundersen Kjevik / Ash Project","type":"REMEDIATION_DEVELOPER"},{"name":"Jonatan Männchen / EEF","type":"COORDINATOR"}]}