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.

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Tue, 11 Aug 2026 20:45:00 +0000

Type Values Removed Values Added
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.
Title Malcolm Vulnerable to Authorization Bypass via URI Normalization Differential in Nginx Lua RBAC
Weaknesses CWE-863
References
Metrics cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-11T20:30:57.901Z

Reserved: 2026-07-15T22:13:00.720Z

Link: CVE-2026-63177

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-11T21:17:44.443

Modified: 2026-08-11T21:17:44.443

Link: CVE-2026-63177

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses