CVE-2026-5590: Zephyrproject Zephyr

Medium severity, CVSS 5.3. EPSS: 0.3% chance of exploitation in the next 30 days.

A race condition during TCP connection teardown can cause tcp_recv() to operate on a connection that has already been released. If tcp_conn_search() returns NULL while processing a SYN packet, a NULL pointer derived from stale context data is passed to tcp_backlog_is_full() and dereferenced without validation, leading to a crash.

Affected products

• Zephyrproject Zephyr: up to and including 4.3.0

Published 2026-04-05. Last modified 2026-07-24.