# 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.

- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Aug 2026
- **Updated:** 12 Aug 2026
- **Also known as:** GHSA-q3mh-4wj7-mq7f

## 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 (Missing Release of Resource after Effective Lifetime)

## 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.

## Is CVE-2026-11811 being exploited?

There is no known exploitation of CVE-2026-11811 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-11811 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-11811 in the wild and no public exploit code.

Affected product: zephyrproject zephyr. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-11811/ (Markdown: https://insights.sbomify.com/CVE-2026-11811/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-11811
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-11811
- OSV: https://osv.dev/vulnerability/CVE-2026-11811

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-11811/
Summaries are generated and may contain mistakes; the official description above is the record.