{"id":"CVE-2026-90447","aliases":["EUVD-2026-76746","GHSA-rh2r-7hqc-wgwc"],"status":"published","title":"Authentication Bypass by Spoofing in Malcolm","description":"A routing rule selects between two different authentication mechanisms for the same downstream service based on the value of a client-supplied request header, rather than on any property the client cannot control. An authenticated user in possession of a shared service credential can set this header to route around the primary role-based authorization check and reach the alternate path's fixed, elevated role instead. This allows a low-privileged authenticated attacker who knows the shared credential to perform actions reserved for a higher-privileged role.","severity":{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0022,"percentile":0.12665,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-290"],"published":"2026-09-11T21:48:51Z","modified":"2026-10-28T02:30:58Z","products":[{"vendor":"cisa","product":"malcolm"},{"vendor":"cisagov","product":"malcolm"}],"references":[{"url":"https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2026/icsa-26-254-01.json","tags":["government-resource","vendor-advisory","advisory"]},{"url":"https://www.cisa.gov/news-events/ics-advisories/icsa-26-254-01","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90447","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-rh2r-7hqc-wgwc"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90447.json","tags":["advisory"]},{"url":"https://github.com/cisagov/Malcolm","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-90447","title":"Authentication Bypass by Spoofing in Malcolm","description":"A routing rule selects between two different authentication mechanisms for the same downstream service based on the value of a client-supplied request header, rather than on any property the client cannot control. An authenticated user in possession of a shared service credential can set this header to route around the primary role-based authorization check and reach the alternate path's fixed, elevated role instead. This allows a low-privileged authenticated attacker who knows the shared credential to perform actions reserved for a higher-privileged role.","status":"published","published":"2026-09-11T21:48:51.996Z","modified":"2026-10-02T21:12:27.669Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","level":"high","assessor":"cna"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-290"],"updated_at":"2026-11-02T13:45:47.885058Z"}],"euvd":[{"id":"EUVD-2026-76746","description":"A routing rule selects between two different authentication mechanisms for the same downstream service based on the value of a client-supplied request header, rather than on any property the client cannot control. An authenticated user in possession of a shared service credential can set this header to route around the primary role-based authorization check and reach the alternate path's fixed, elevated role instead. This allows a low-privileged authenticated attacker who knows the shared credential to perform actions reserved for a higher-privileged role.","status":"published","published":"2026-09-11T21:48:51Z","modified":"2026-10-02T21:12:27Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T17:27:41.962371Z"}],"ghsa":[{"id":"GHSA-rh2r-7hqc-wgwc","title":"A routing rule selects between two different authentication mechanisms for the same downstream...","description":"A routing rule selects between two different authentication mechanisms for the same downstream service based on the value of a client-supplied request header, rather than on any property the client cannot control. An authenticated user in possession of a shared service credential can set this header to route around the primary role-based authorization check and reach the alternate path's fixed, elevated role instead. This allows a low-privileged authenticated attacker who knows the shared credential to perform actions reserved for a higher-privileged role.","status":"published","published":"2026-09-12T00:31:28Z","modified":"2026-10-03T00:31:12Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/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"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium"}],"cwes":["CWE-290"],"updated_at":"2026-11-02T15:12:44.258575Z"}],"nvd":[{"id":"CVE-2026-90447","description":"A routing rule selects between two different authentication mechanisms for the same downstream service based on the value of a client-supplied request header, rather than on any property the client cannot control. An authenticated user in possession of a shared service credential can set this header to route around the primary role-based authorization check and reach the alternate path's fixed, elevated role instead. This allows a low-privileged authenticated attacker who knows the shared credential to perform actions reserved for a higher-privileged role.","status":"published","published":"2026-09-11T22:16:46.797Z","modified":"2026-10-02T22:16:55.19Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/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"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-290"],"updated_at":"2026-11-02T14:12:46.62721Z"}],"osv":[{"id":"CVE-2026-90447","title":"Authentication Bypass by Spoofing in Malcolm","description":"A routing rule selects between two different authentication mechanisms for the same downstream service based on the value of a client-supplied request header, rather than on any property the client cannot control. An authenticated user in possession of a shared service credential can set this header to route around the primary role-based authorization check and reach the alternate path's fixed, elevated role instead. This allows a low-privileged authenticated attacker who knows the shared credential to perform actions reserved for a higher-privileged role.","status":"published","published":"2026-09-11T21:48:51.996Z","modified":"2026-10-28T02:30:58.057133323Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-290"],"updated_at":"2026-11-02T15:45:20.269367Z"}]}}