AUGUST 17, 2026
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Case File

CVE-2026-5067

CRITICAL · CVSS 9.8 EPSS 0.64% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2026-06-09 · Last synced 2026-08-04

CyberRota Analysis

This is a critical severity vulnerability with a CVSS score of 9.8. Public exploit code or proof-of-concept references have been detected in its references. It may be remotely exploitable. Exploitation may require the attacker to be authenticated. It may lead to a denial-of-service condition.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Detected Signals
code execution
GitHub PoC Links

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-5067
Severity
CRITICAL
CVSS
9.8
EPSS
0.64%

Original NVD 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.

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