CVE-2026-11811 Socket file-descriptor leak in UpdateHub OTA client start_coap_client() leading to resource-exhaustion DoS
A socket descriptor leak in the UpdateHub OTA client allows remote attackers to exhaust network resources and cause device-wide denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-11811?
CVE-2026-11811 is a low-severity denial of service vulnerability in zephyrproject zephyr, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-772
Which versions are affected by CVE-2026-11811?
How do I fix CVE-2026-11811?
No fix has been published for CVE-2026-11811 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-11811 being exploited?
There is no known exploitation of CVE-2026-11811 in the wild and no public exploit code.
Sources
Also known as GHSA-q3mh-4wj7-mq7f.