---
id: CVE-2026-5066
title: >-
  A potential out-of-bounds write/read exists in the TLS socket connect path of
  the network sockets subsystem (subsys/net/lib/sockets/sockets_tls.c)
summary: >-
  A potential out-of-bounds write/read exists in the TLS socket connect path of
  the network sockets subsystem (subsys/net/lib/sockets/sockets_tls.c). When the
  TLS session cache is enabled, tls_session_store() and tls_session_restore()
  memc…
severity: medium
cvss: 6.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-787
vendor: zephyrproject
product: zephyr
affected:
  - zephyr <= 4.3.0
published: '2026-06-04'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T23:17:37.257'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-5066'
references:
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wgrc-jrf6-24f3
    label: vulnerabilities@zephyrproject.org
  - url: >-
      https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wgrc-jrf6-24f3
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
epss: 0.0032
epssPercentile: 0.24815
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-06-05T18:26:28.322491Z'
ingestedAt: '2026-10-15T22:48:25.574Z'
---

## Overview

A potential out-of-bounds write/read exists in the TLS socket connect path of the network sockets subsystem (subsys/net/lib/sockets/sockets_tls.c). When the TLS session cache is enabled, tls_session_store() and tls_session_restore() memcpy the caller-supplied address into a fixed-size buffer using the caller-controlled addrlen value without validating it against the destination size. struct net_sockaddr is an opaque type, so an application can pass an addrlen larger than sizeof(struct net_sockaddr) (for example 128 bytes into a 24-byte stack buffer), causing the memcpy to read and write past the end of the address memory used by the TLS session cache. This out-of-bounds write can lead to a crash and denial of service, and potentially to arbitrary code execution.

## Affected

- `zephyr <= 4.3.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.