Malcolm's nginx Lua role-based access control (RBAC) layer decides whether an authenticated user may reach a role-restricted path (e.g. /htadmin, /auth, /admin_login, /arkime/api/esadmin, NetBox, upload endpoints) by pattern-matching the raw, percent-encoded request URI. Nginx itself, however, selects which location block actually serves the request using the percent-decoded, normalized URI. Because the RBAC check never percent-decodes its input, an authenticated low-privilege user can request an admin-only path using percent-encoding (e.g. /%68tadmin.php) and have nginx route it to the restricted location while the Lua RBAC gate evaluating the un-decoded raw string finds no matching restriction and grants access.

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Advisories

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Fixes

Solution

Malcolm version 26.08.0 addresses this issue. For more information, see  https://github.com/cisagov/Malcolm/security/advisories/GHSA-f2v6-8cj4-mhr6 .


Workaround

No workaround given by the vendor.

History

Tue, 18 Aug 2026 21:15:00 +0000

Type Values Removed Values Added
First Time appeared Cisagov
Cisagov malcolm
Vendors & Products Cisagov
Cisagov malcolm

Tue, 18 Aug 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 18 Aug 2026 19:30:00 +0000

Type Values Removed Values Added
Description Malcolm's nginx Lua role-based access control (RBAC) layer decides whether an authenticated user may reach a role-restricted path (e.g. /htadmin, /auth, /admin_login, /arkime/api/esadmin, NetBox, upload endpoints) by pattern-matching the raw, percent-encoded request URI. Nginx itself, however, selects which location block actually serves the request using the percent-decoded, normalized URI. Because the RBAC check never percent-decodes its input, an authenticated low-privilege user can request an admin-only path using percent-encoding (e.g. /%68tadmin.php) and have nginx route it to the restricted location while the Lua RBAC gate evaluating the un-decoded raw string finds no matching restriction and grants access.
Title Incorrect Authorization in CISA Malcolm
Weaknesses CWE-863
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: icscert

Published:

Updated: 2026-08-18T19:47:33.551Z

Reserved: 2026-08-12T21:15:02.239Z

Link: CVE-2026-19670

cve-icon Vulnrichment

Updated: 2026-08-18T19:47:13.930Z

cve-icon NVD

Status : Received

Published: 2026-08-18T20:17:13.473

Modified: 2026-08-18T20:17:13.473

Link: CVE-2026-19670

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-18T21:30:04Z

Weaknesses