CVE-2026-107336
Received Received - Intake

Malcolm nginx Reverse Proxy Authentication Bypass via Case-Insensitive Matcher

Publication date: 2026-10-08

Last updated on: 2026-10-08

Assigner: ICS-CERT

Description
Malcolm's front nginx reverse proxy defines a "Dashboards → Arkime shortcut" location using a case-insensitive regex matcher but a case-sensitive rewrite. A request whose path segment is not exact-lowercase (for example /IDDASH2ARK/...) enters the location (the matcher fires) but evades the rewrite (no redirect is issued), so nginx falls through to the location's proxy_pass to the Arkime backend. That location is the one proxied location in the shipped config that does not include the per-location authentication file, so the request reaches Arkime unauthenticated. The same location also forwards a client-supplied X-Forwarded-User header un-overwritten, and Arkime is configured to trust X-Forwarded-User as the authenticated username — so an unauthenticated network caller can reach the Arkime backend while supplying a forged, auto-provisioned identity.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-10-08
Last Modified
2026-10-08
Generated
2026-10-08
AI Q&A
2026-10-08
EPSS Evaluated
N/A
NVD
CVE-2026-107336
EUVD
EUVD-2026-95115

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
CISA Malcolm 0

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-290 This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
CWE-863 The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
CWE-441 The product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability involves Malcolm's front nginx reverse proxy using a case-insensitive regex matcher but a case-sensitive rewrite for a specific location. A request with a path segment not in exact lowercase (e.g., /IDDASH2ARK/...) triggers the location but bypasses the rewrite, causing nginx to proxy the request to the Arkime backend without authentication. The location also forwards a client-supplied X-Forwarded-User header, which Arkime trusts as the authenticated username, allowing an unauthenticated attacker to forge an identity and access the backend.

Detection Guidance

Check nginx access logs for requests to /IDDASH2ARK/... or similar case variations that bypass the rewrite rule. Look for unauthenticated proxy passes to Arkime backend without authentication headers.

Impact Analysis

An attacker could exploit this to access the Arkime backend without proper authentication, potentially viewing sensitive data or performing unauthorized actions. The forged identity via X-Forwarded-User could allow impersonation of legitimate users, leading to data breaches or system misuse.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating confidentiality requirements in GDPR and HIPAA. Non-compliance may result in legal penalties, reputational damage, and failure to meet regulatory standards for data protection and access control.

Mitigation Strategies

Update nginx configuration to enforce exact lowercase matching for the Dashboards shortcut location. Ensure all proxy_pass locations include authentication checks and overwrite X-Forwarded-User headers.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-107336. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart