---
id: CVE-2026-11810
title: >-
  NULL-pointer dereference in UpdateHub OTA agent on empty inner metadata array
  (remote DoS)
summary: >-
  The UpdateHub firmware-update agent's probe handler (z_impl_updatehub_probe()
  in subsys/mgmt/updatehub/updatehub.c) parses the JSON metadata returned by the
  update server into a fixed two-level nested-array struct. After parsing it
  valid…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-476
vendor: zephyrproject
product: zephyr
affected:
  - zephyr >= 3.7.0 < 4.3.2
  - zephyr >= 4.4.0 < 4.4.2
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-08-11T14:32:27.987817Z'
published: '2026-08-10'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T04:59:13.740Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-11810'
references:
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/commit/3424082022cb39d568434021b1d6f68b6a7fb3bf
    label: Fix commit
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-jfpc-324j-84ww
    label: GHSA-jfpc-324j-84ww
tags:
  - cve.org
epss: 0.00467
epssPercentile: 0.40574
ingestedAt: '2026-11-05T20:33:06.699Z'
---

## Overview

The UpdateHub firmware-update agent's probe handler (z_impl_updatehub_probe() in subsys/mgmt/updatehub/updatehub.c) parses the JSON metadata returned by the update server into a fixed two-level nested-array struct. After parsing it validates only the outer array length (objects_len != 2) and then dereferences objects[1].objects[0].objects.sha256sum via strlen() without checking that the inner object array of element [1] is non-empty.

The metadata is attacker-influenceable network input: the agent fetches it over CoAP from the configured UpdateHub server during its routine OTA probe. A malicious or compromised update server (or, when DTLS is disabled, a network man-in-the-middle) can return a response whose second outer object array is empty. Because the parse target is zero-initialised, the corresponding objects[1].objects[0].objects.sha256sum pointer is NULL, and the subsequent strlen() dereferences address zero. The same defect exists in both the 'any boards' and 'some boards' metadata layouts.

The resulting CPU fault is fatal under Zephyr's default error handling, halting or resetting the device, so the flaw is a remotely triggerable denial of service. Impact is limited to availability; it is a read from NULL with no out-of-bounds write, memory corruption, or information disclosure. The fix rejects metadata whose inner object array is empty before any dereference, on both layouts.

## Affected

- `zephyr >= 3.7.0 < 4.3.2`
- `zephyr >= 4.4.0 < 4.4.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.