What is CVE-2026-5590?

CVE-2026-5590 is a medium-severity vulnerability in Zephyrproject Zephyr, classified under NULL Pointer Dereference. CVSS score: 6.4/10. Published 2026-04-05.

How severe is CVE-2026-5590?

Medium severity. CVSS v3 base score is 6.4 out of 10.

NULL pointer dereference in Zephyrproject Zephyr

CVE-2026-5590

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.

Published 2026-04-05 · last modified 2026-07-24.

CVSS v3 metric

CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H.

EPSS exploit prediction

EPSS: 0.003 (17.8th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 17.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

References

github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-4vqm-pw24-g9jp (Exploit, Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-5590?: CVE-2026-5590 is a medium-severity vulnerability in Zephyrproject Zephyr, classified under NULL Pointer Dereference. CVSS score: 6.4/10. Published 2026-04-05.
How severe is CVE-2026-5590?: Medium severity. CVSS v3 base score is 6.4 out of 10.