CVE-2026-63177: high-severity vulnerability in cisagov Malcolm
Malcolm Vulnerable to Authorization Bypass via URI Normalization Differential in Nginx Lua RBAC
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.1epss 0.4%
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.
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
Affected products
cisagov · MalcolmRelated CVEs — cisagov Malcolm
In the same product, most dangerous first.
CVE-2026-55676HIGHMalcolm vulnerable to RCE via unrestricted .php upload to the file-upload componentEPSS 0.6%CVE-2026-63133HIGHMalcolm has Uncontrolled Resource Consumption in Archive Extraction (Inode-Exhaustion DoS)EPSS 0.5%CVE-2026-63134MEDIUMMalcolm's Path Traversal in Archive Extraction Allows Arbitrary Directory CreationEPSS 0.4%