Vulnerability 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 Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Zephyrproject | Zephyr | >= 3.7.0, <= 4.3.0 |
Related Weaknesses (CWE)
References
- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wgr4-9pwq-ExploitPatchVendor Advisory
- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wgr4-9pwq-ExploitPatchVendor Advisory
FAQ
What is CVE-2026-5067?
CVE-2026-5067 is a vulnerability with a CVSS score of 9.8 (CRITICAL). 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 heade...
How severe is CVE-2026-5067?
CVE-2026-5067 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-5067?
Check the references section above for vendor advisories and patch information. Affected products include: Zephyrproject Zephyr.