A remote, unauthenticated attacker can trigger memory corruption in Zephyr's HTTP server WebSocket upgrade path by sending a crafted Sec-WebSocket-Key header. The HTTP/1 header parser copies the header into a fixed-size buffer using a bounded copy that does not guarantee NUL termination when the input length reaches the buffer size. During upgrade handling the buffer is copied to a local stack buffer and passed to strlen(); if no NUL exists in-bounds, strlen() reads beyond the stack buffer and subsequent concatenation with the WebSocket magic string can write out of bounds. This leads to out-of-bounds read and write on stack memory, resulting in crash (denial of service) and potentially code execution. The path is reachable when CONFIG_HTTP_SERVER_WEBSOCKET is enabled.

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History

Tue, 09 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Tue, 09 Jun 2026 07:45:00 +0000

Type Values Removed Values Added
First Time appeared Zephyrproject-rtos
Zephyrproject-rtos zephyr
Vendors & Products Zephyrproject-rtos
Zephyrproject-rtos zephyr

Tue, 09 Jun 2026 06:15:00 +0000

Type Values Removed Values Added
Description A remote, unauthenticated attacker can trigger memory corruption in Zephyr's HTTP server WebSocket upgrade path by sending a crafted Sec-WebSocket-Key header. The HTTP/1 header parser copies the header into a fixed-size buffer using a bounded copy that does not guarantee NUL termination when the input length reaches the buffer size. During upgrade handling the buffer is copied to a local stack buffer and passed to strlen(); if no NUL exists in-bounds, strlen() reads beyond the stack buffer and subsequent concatenation with the WebSocket magic string can write out of bounds. This leads to out-of-bounds read and write on stack memory, resulting in crash (denial of service) and potentially code execution. The path is reachable when CONFIG_HTTP_SERVER_WEBSOCKET is enabled.
Title Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key
Weaknesses CWE-170
CWE-787
References
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: zephyr

Published:

Updated: 2026-06-09T13:12:08.853Z

Reserved: 2026-03-27T22:30:27.757Z

Link: CVE-2026-5067

cve-icon Vulnrichment

Updated: 2026-06-09T13:12:04.965Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-06-09T06:16:53.920

Modified: 2026-06-09T14:16:45.247

Link: CVE-2026-5067

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-09T07:30:26Z

Weaknesses