CVE-2026-63177

high

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.

References

https://www.cisa.gov/news-events/ics-advisories/icsa-26-230-01

https://github.com/cisagov/Malcolm/security/advisories/GHSA-m5fr-rv3h-xg2r

https://github.com/cisagov/Malcolm/releases/tag/v26.07.0

https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-230-01.json

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-56972

Details

Source: Mitre, NVD

Published: 2026-08-11

Updated: 2026-10-02

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:P/A:N

Severity: High

CVSS v3

Base Score: 7.1

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Severity: High

CVSS v4

Base 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

Severity: High

EPSS

EPSS: 0.00369