CVE-2026-5067

CRITICAL EPSS 38.9%
Published Jun 9, 20262w ago · Modified Jun 17, 20261w ago
9.8 CVSS 3.1
Critical
Find Similar
Published Jun 9, 2026 2w ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
9.8
Exploitability
3.9
Impact
5.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
38.9% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 2

CWE-170
CWE-787 Out-of-bounds Write Memory Safety

References 1

  • github.com https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wgr4-9pwq-94vj

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.