CVE-2026-5067
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk36th percentile — higher than 36% of all known CVEs
Summary
A remote, unauthenticated attacker can trigger memory corruption in Zephyr's HTTP server by sending a crafted Sec-WebSocket-Key header. A flaw in the HTTP/1 header parser leads to out-of-bounds read and write on stack memory, resulting in crash (denial of service) and potentially code execution.
Risk Assessment
This vulnerability poses a risk of server crash and remote code execution, which can lead to serious security implications for the organization.
Recommendation
It is recommended to disable CONFIG_HTTP_SERVER_WEBSOCKET to minimize risk, and to monitor and update the system to mitigate this vulnerability.
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.