{"id":"CVE-2026-5067","title":"Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key","summary":"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 bo…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-170","CWE-787"],"vendor":"zephyrproject-rtos","product":"Zephyr","affected":["Zephyr >= 3.7.0 < 4.3.1"],"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"total","timestamp":"2026-06-09T13:11:48.752906Z"},"exploitAvailable":true,"published":"2026-06-09","updated":"2026-10-15","sourceUpdated":"2026-10-15T22:10:25.382Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-5067","references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wgr4-9pwq-94vj"}],"tags":["cve.org","exploit-available"],"epss":0.00865,"epssPercentile":0.57756,"ingestedAt":"2026-10-15T22:48:25.574Z","slug":"CVE-2026-5067","body":"## Overview\n\nA 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.\n\n## Affected\n\n- `Zephyr >= 3.7.0 < 4.3.1`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"abyssal","depthScore":66,"depthScoreParts":{"impact":53.9,"likelihood":0.2,"exploitation":12,"ransomware":0},"changes":[]}