CVE-2026-5067
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk47th percentile - higher than 47% of all known CVEs
Summary
Zephyr OS has a memory corruption vulnerability in the HTTP server WebSocket upgrade path. An unauthenticated remote attacker can trigger it by sending a crafted Sec-WebSocket-Key header. The bounded copy does not guarantee NUL termination, leading to out-of-bounds read/write on stack.
Risk Assessment
An attacker can cause system crashes (denial of service) or potentially achieve remote code execution. The path is reachable when CONFIG_HTTP_SERVER_WEBSOCKET is enabled.
Recommendation
Update Zephyr to a version containing the fix. Disable CONFIG_HTTP_SERVER_WEBSOCKET if not required.
Original NVD description (English source)
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.