{"id":"CVE-2026-63177","aliases":["EUVD-2026-56972","GHSA-m5fr-rv3h-xg2r"],"status":"published","title":"Malcolm Vulnerable to Authorization Bypass via URI Normalization Differential in Nginx Lua RBAC","description":"Malcolm is a network traffic analysis tool suite. Prior to version 26.07.0, role-based access control enforced in the Nginx OpenResty Lua layer evaluates the raw, unnormalized `ngx.var.request_uri`, while Nginx itself routes requests using the normalized path. An authenticated low-privilege user can prepend a traversal segment (for example `/x/../upload/...`) so that Nginx routes the request to a restricted backend while the Lua role check fails to match any rule and falls open, granting access it should deny. Version 26.07.0 fixes the issue.","severity":{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00369,"percentile":0.31033,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-863"],"published":"2026-08-11T20:30:57Z","modified":"2026-10-28T02:30:22Z","products":[{"vendor":"cisagov","product":"malcolm"}],"references":[{"url":"https://github.com/cisagov/Malcolm/security/advisories/GHSA-m5fr-rv3h-xg2r","tags":["x_refsource_CONFIRM","advisory"]},{"url":"https://github.com/cisagov/Malcolm/releases/tag/v26.07.0","tags":["x_refsource_MISC","web"]},{"url":"https://www.cisa.gov/news-events/ics-advisories/icsa-26-230-01","tags":["advisory"]},{"url":"https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-230-01.json","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63177.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63177","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-63177","title":"Malcolm Vulnerable to Authorization Bypass via URI Normalization Differential in Nginx Lua RBAC","description":"Malcolm is a network traffic analysis tool suite. Prior to version 26.07.0, role-based access control enforced in the Nginx OpenResty Lua layer evaluates the raw, unnormalized `ngx.var.request_uri`, while Nginx itself routes requests using the normalized path. An authenticated low-privilege user can prepend a traversal segment (for example `/x/../upload/...`) so that Nginx routes the request to a restricted backend while the Lua role check fails to match any rule and falls open, granting access it should deny. Version 26.07.0 fixes the issue.","status":"published","published":"2026-08-11T20:30:57.901Z","modified":"2026-10-02T20:27:08.611Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N","level":"high","assessor":"cna"},{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N","level":"high","assessor":"cna"}],"cwes":["CWE-863"],"updated_at":"2026-11-02T14:19:55.914391Z"}],"euvd":[{"id":"EUVD-2026-56972","description":"Malcolm is a network traffic analysis tool suite. Prior to version 26.07.0, role-based access control enforced in the Nginx OpenResty Lua layer evaluates the raw, unnormalized `ngx.var.request_uri`, while Nginx itself routes requests using the normalized path. An authenticated low-privilege user can prepend a traversal segment (for example `/x/../upload/...`) so that Nginx routes the request to a restricted backend while the Lua role check fails to match any rule and falls open, granting access it should deny. Version 26.07.0 fixes the issue.","status":"published","published":"2026-08-11T20:30:57Z","modified":"2026-10-02T20:27:08Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T17:27:41.962371Z"}],"nvd":[{"id":"CVE-2026-63177","description":"Malcolm is a network traffic analysis tool suite. Prior to version 26.07.0, role-based access control enforced in the Nginx OpenResty Lua layer evaluates the raw, unnormalized `ngx.var.request_uri`, while Nginx itself routes requests using the normalized path. An authenticated low-privilege user can prepend a traversal segment (for example `/x/../upload/...`) so that Nginx routes the request to a restricted backend while the Lua role check fails to match any rule and falls open, granting access it should deny. Version 26.07.0 fixes the issue.","status":"published","published":"2026-08-11T21:17:44.443Z","modified":"2026-10-24T16:10:00.153Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/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":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N","level":"high","assessor":"secondary"}],"cwes":["CWE-863"],"updated_at":"2026-11-02T14:12:36.880938Z"}],"osv":[{"id":"CVE-2026-63177","title":"Malcolm Vulnerable to Authorization Bypass via URI Normalization Differential in Nginx Lua RBAC","description":"Malcolm is a network traffic analysis tool suite. Prior to version 26.07.0, role-based access control enforced in the Nginx OpenResty Lua layer evaluates the raw, unnormalized `ngx.var.request_uri`, while Nginx itself routes requests using the normalized path. An authenticated low-privilege user can prepend a traversal segment (for example `/x/../upload/...`) so that Nginx routes the request to a restricted backend while the Lua role check fails to match any rule and falls open, granting access it should deny. Version 26.07.0 fixes the issue.","status":"published","published":"2026-08-11T20:30:57.901Z","modified":"2026-10-28T02:30:22.601461069Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-863"],"updated_at":"2026-11-02T15:45:13.306117Z"}]}}