CVE-2026-123033
Received Received - Intake

Authentication Bypass in TrueNAS SCALE middlewared

Vulnerability report for CVE-2026-123033, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-11-05

Last updated on: 2026-11-05

Assigner: MITRE

Description

Authentication bypass in the HA heartbeat origin check in middlewared in TrueNAS SCALE before 25.10.8 (and in release trains before their respective fixes) allows an attacker on the same network segment to achieve unauthenticated full-administrator API access and execute commands as root. middlewared registers the HA peer-authentication hook (ha_permission) unconditionally, with no failover-licence or heartbeat-interface check. An unauthenticated connection whose TCP peer address is a hardcoded HA heartbeat address (169.254.10.1 or 169.254.10.2) and whose peer port is <= 1024 is granted a node credential that is authorized for every API method and treated as full administrator. Both conditions are properties of the attacker's own socket, and thus an attacker on the same layer-2 segment satisfies them without forging anything. The hook is present on non-HA, unlicensed, single-node Community Edition installations. The fix additionally requires that the connection terminate on the HA heartbeat listener (a local address/port the attacker cannot control).

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Meta Information

Published
2026-11-05
Last Modified
2026-11-05
Generated
2026-11-05
AI Q&A
2026-11-05
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
iXsystems TrueNAS SCALE 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-290 This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.

Attack-Flow Graph

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Executive Summary

This vulnerability is an authentication bypass in TrueNAS SCALE's HA heartbeat system. It allows an attacker on the same network segment to gain full administrative API access without authentication by exploiting how middlewared handles TCP peer addresses and ports. The flaw grants node credentials to any connection with a peer address matching HA heartbeat IPs (169.254.10.1 or 169.254.10.2) and a source port <= 1024.

Detection Guidance

To detect this vulnerability, monitor network traffic for unauthorized connections to the TrueNAS management interface from the HA heartbeat addresses (169.254.10.1 or 169.254.10.2) with source ports <= 1024. Use tools like tcpdump or Wireshark to capture traffic on the TrueNAS management interface and filter for these conditions.

Impact Analysis

An attacker could exploit this to read sensitive configuration data, bypass security controls like IP allowlists, execute arbitrary commands as root, and avoid detection in audit logs. This applies even to non-HA single-node systems since the vulnerable middleware is always active.

Mitigation Strategies

Immediately isolate the TrueNAS management interface on a dedicated, trusted network to prevent untrusted hosts from accessing the HA heartbeat address range. Upgrade to TrueNAS SCALE 25.10.8 or later to apply the fix. Ensure no untrusted devices share the same layer-2 network segment as the TrueNAS management interface.

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