CVE-2026-11811

Received Received - Intake

Socket Descriptor Leak in Zephyr UpdateHub

Publication date: 2026-08-10

Last updated on: 2026-08-10

Assigner: Zephyr Project

Description

The UpdateHub over-the-air update client's start_coap_client() in subsys/mgmt/updatehub/updatehub.c leaks the CoAP/DTLS socket descriptor on its connection-setup failure paths. The shared error: cleanup gated socket closing on a ret > 0 flag, but ret was set to -1 immediately after the socket was created, so when zsock_setsockopt() (DTLS) or zsock_connect() subsequently failed the gate was false and cleanup_connection() was never called. The open descriptor in the global ctx.sock was then overwritten by the next attempt, permanently leaking it from the socket / net_context pool until reboot. The failing setup path is reached every time the OTA client tries to contact the UpdateHub server and the connection cannot be established — driven automatically by the periodic autohandler() poll (and on demand via the updatehub_probe()/updatehub_update() API or the updatehub run shell command). The DTLS handshake/connect outcome is influenceable by a network or on-path attacker who drops, resets, or otherwise disrupts traffic to the server, and also fails naturally whenever the server is unreachable. Each failed attempt permanently leaks one descriptor; once the shared socket pool is exhausted, networking degrades device-wide until the device is rebooted, a denial-of-service condition. Severity is low because the leak rate is bounded by the configured OTA poll interval (default once per 24 hours), the effect is gradual and recovered by reboot, and only builds with the UpdateHub client enabled are affected. There is no memory-corruption, information-disclosure, or authentication impact.

CVSS Scores

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Meta Information

Published

2026-08-10

Last Modified

2026-08-10

Generated

2026-08-11

AI Q&A

2026-08-11

EPSS Evaluated

N/A

NVD

CVE-2026-11811

Affected Vendors & Products

Vendor	Product	Version / Range
zephyrproject	updatehub	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-772	The product does not release a resource after its effective lifetime has ended, i.e., after the resource is no longer needed.

Attack-Flow Graph

Executive Summary

This vulnerability involves the UpdateHub OTA update client leaking CoAP/DTLS socket descriptors when connection setup fails. The issue occurs because the error handling logic incorrectly checks a return value flag, preventing proper cleanup of the socket. Each failed connection attempt permanently leaks a descriptor until the socket pool is exhausted, causing network degradation.

Detection Guidance

This vulnerability is specific to the UpdateHub OTA client in Zephyr RTOS and may not have direct network or system-level detection commands. Monitor for symptoms like gradual network degradation or socket exhaustion on affected devices. Check for repeated failed OTA connection attempts in logs or use system monitoring tools to track open sockets and descriptor leaks.

Impact Analysis

The vulnerability can lead to a denial-of-service condition where networking degrades or fails entirely as socket descriptors are exhausted. This happens gradually with each failed OTA update attempt, which may occur due to network issues or server unavailability. The impact is limited by the OTA poll interval and resolved by rebooting the device.

Mitigation Strategies

Disable the UpdateHub client if not required. If enabled, reduce the OTA poll interval to minimize leak rate. Reboot affected devices to clear leaked descriptors. Apply patches from the Zephyr project once available. Monitor network performance and socket usage for signs of exhaustion.

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