---
id: CVE-2026-63177
title: Malcolm is a network traffic analysis tool suite
summary: >-
  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 usi…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N'
cwe:
  - CWE-863
vendor: cisagov
product: Malcolm
affected:
  - Malcolm < 26.07.0
published: '2026-08-11'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T21:16:56.163'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63177'
references:
  - url: >-
      https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-230-01.json
    label: ics-cert@hq.dhs.gov
  - url: 'https://github.com/cisagov/Malcolm/releases/tag/v26.07.0'
    label: ics-cert@hq.dhs.gov
  - url: 'https://github.com/cisagov/Malcolm/security/advisories/GHSA-m5fr-rv3h-xg2r'
    label: ics-cert@hq.dhs.gov
  - url: 'https://www.cisa.gov/news-events/ics-advisories/icsa-26-230-01'
    label: ics-cert@hq.dhs.gov
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-08-12T22:07:37.481958Z'
epss: 0.00369
epssPercentile: 0.3058
ingestedAt: '2026-09-09T21:22:45.530Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.