CVE-2026-22624: HIKSEMI NAS Auth Bypass Vulnerability

CVE-2026-22624 Overview

CVE-2026-22624 is a Broken Access Control vulnerability affecting certain HIKSEMI NAS (Network Attached Storage) products. Due to inadequate access control mechanisms, authenticated users can manipulate other users' file resources without proper authorization. This vulnerability allows for unauthorized horizontal privilege escalation where one authenticated user can access and potentially modify files belonging to other users on the same NAS device.

Critical Impact

Authenticated users can access and manipulate file resources belonging to other users, potentially leading to unauthorized data access, modification, or deletion across shared storage environments.

Affected Products

• HIKSEMI NAS products (specific models not disclosed in advisory)

Discovery Timeline

• 2026-01-30 - CVE CVE-2026-22624 published to NVD
• 2026-02-04 - Last updated in NVD database

Technical Details for CVE-2026-22624

Vulnerability Analysis

This vulnerability stems from inadequate access control implementation within HIKSEMI NAS products. The flaw allows authenticated users to bypass authorization checks when accessing file resources. While the attacker must possess valid credentials to exploit this vulnerability, once authenticated, they can access files outside their authorized scope.

The network-accessible nature of NAS devices, combined with low attack complexity and no required user interaction, makes this vulnerability relatively straightforward to exploit for any authenticated user on the system. The impact is primarily focused on confidentiality, as attackers can read files belonging to other users without proper authorization.

Root Cause

The root cause of this vulnerability is improper access control validation in the file resource management system. The application fails to properly verify whether an authenticated user has the appropriate permissions to access specific file resources before granting access. This represents a classic Insecure Direct Object Reference (IDOR) pattern where the system trusts user-supplied identifiers without validating ownership or access rights.

Attack Vector

The attack vector is network-based and requires low-privilege authentication. An attacker with valid credentials on the HIKSEMI NAS system can craft requests to access file resources belonging to other users. The exploitation does not require any special privileges beyond basic authentication, and no user interaction is needed from the victim.

The attack flow typically involves:

1. Authenticating to the NAS device with valid credentials
2. Identifying or enumerating file resource identifiers belonging to other users
3. Submitting requests to access those resources, bypassing authorization checks
4. Successfully retrieving or manipulating the unauthorized files

Detection Methods for CVE-2026-22624

Indicators of Compromise

• Unusual file access patterns from authenticated users accessing resources outside their designated directories
• Access logs showing users retrieving files or metadata from directories they do not own
• Anomalous API requests targeting file resource endpoints with identifiers belonging to other users

Detection Strategies

• Monitor NAS access logs for cross-user file access attempts that violate expected access patterns
• Implement file integrity monitoring to detect unauthorized modifications to user files
• Deploy network traffic analysis to identify unusual patterns in file access requests

Monitoring Recommendations

• Enable comprehensive audit logging on HIKSEMI NAS devices to capture all file access events
• Configure alerts for any file access events where the requesting user does not match the file owner
• Regularly review access logs for patterns indicating unauthorized cross-user file access

How to Mitigate CVE-2026-22624

Immediate Actions Required

• Review and audit current user access permissions on affected HIKSEMI NAS devices
• Limit network exposure of NAS devices to trusted networks only
• Monitor for any unauthorized file access activity in system logs
• Apply firmware updates from HIKSEMI as they become available

Patch Information

HIKSEMI has published a security advisory regarding this vulnerability. Administrators should consult the Hiksemi Security Advisory for official patch information and firmware updates. It is recommended to apply the latest firmware version that addresses this access control vulnerability.

Workarounds

• Restrict network access to the NAS device using firewall rules to limit exposure to trusted hosts only
• Implement network segmentation to isolate NAS devices from untrusted network segments
• Review and minimize the number of authenticated user accounts on the device
• Consider disabling remote access features until patches are applied

# Example firewall rule to restrict NAS access (adjust IP addresses as needed)
# Allow only trusted management network
iptables -A INPUT -s 192.168.1.0/24 -d <NAS_IP> -p tcp --dport 443 -j ACCEPT
iptables -A INPUT -d <NAS_IP> -p tcp --dport 443 -j DROP