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OpenAdvisories
High · 7.1 CVE-2026-63177 EUVD-2026-56972

Malcolm Vulnerable to Authorization Bypass via URI Normalization Differential in Nginx Lua RBAC

Published Aug 11, 2026 · Updated Oct 2, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
cisagov Malcolm < 26.07.0 26.07.0

Advisories 1

References