Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
zephyrproject-rtos Zephyr — Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key
AV AC PR UI S C I A CVSS EPSS %ile KEV
N L N N U H H H 9.8 .0064 48.0 —
AFFECTED
Product Versions Fixed
Zephyr 3.7.0 – —
TIMELINE
Mar 27 Reserved by zephyr
Jun 9 EXPLOIT PUBLISHED — CVE-2026-5067 (zephyrproject-rtos Zephyr). Public exploit reference added.
Jun 9 Published (CNA: zephyr)
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.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| March 27, 2026 | Reserved | Reserved by zephyr |
| June 9, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-5067 (zephyrproject-rtos Zephyr). Public exploit reference added. |
| June 9, 2026 | Published | Published (CNA: zephyr) |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| zephyrproject-rtos | Zephyr | — | 3.7.0 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-5067 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.