CVE-2026-19670

Summary

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.

Affected Software

Weaknesses

• CWE-863: CWE-863 Incorrect Authorization

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: poc
  • Automatable: no
  • Technical Impact: partial

Additional References

• https://github.com/cisagov/Malcolm/security/advisories/GHSA-f2v6-8cj4-mhr6

References

• https://www.cisa.gov/news-events/ics-advisories/icsa-26-230-01
• https://github.com/cisagov/Malcolm/security/advisories/GHSA-f2v6-8cj4-mhr6

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