CVE-2026-11811Network attack vector

Device-wide network disruption via leaked UpdateHub sockets

Published Aug 10, 2026 · Updated Aug 10, 2026

Denial of service in Zephyr RTOS 2.0.0 through 4.4.1 allows remote attackers to exhaust network sockets via failed UpdateHub connections. The start_coap_client() error path tests ret > 0 after setting ret to -1, so failed DTLS setup or connection skips cleanup and the next attempt overwrites ctx.sock. Builds with CONFIG_UPDATEHUB enabled leak one descriptor per failed attempt until device-wide networking degrades and a reboot restores service.

CVSS severity3.7
Low
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Zephyr RTOS 2.0.0 through 4.4.1 allows remote attackers to exhaust network sockets via failed UpdateHub connections. The start_coap_client() error path tests ret > 0 after setting ret to -1, so failed DTLS setup or connection skips cleanup and the next attempt overwrites ctx.sock. Builds with CONFIG_UPDATEHUB enabled leak one descriptor per failed attempt until device-wide networking degrades and a reboot restores service.

The record

CVE
CVE-2026-11811
Published
Aug 10, 2026
Updated
Aug 10, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-772, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.0.0 <4.4.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=2.0.0 <4.4.2

Published CVSS scores

3.7Zephyr ProjectCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-772Missing Release of Resource after Effective Lifetime
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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