# CVE-2026-10639: Zephyr OS use-after-free in ICMPv4 echo request handler

Source: https://junglewise.ai/threats/cve-2026-10639-zephyr-os-use-after-free-in-icmpv4-echo-request-handler  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-16. Updated: 2026-06-16  
License: CC BY 4.0 with a link back

CVE-2026-10639 · Severity: medium · CVSS 4.8 · Published 2026-06-16

Zephyr is an open-source operating system designed for resource-constrained IoT devices. A flaw in its networking component allows a remote attacker to potentially crash a device or corrupt its internal network statistics by sending a standard ping request. This occurs because the system attempts to update its internal counters using information from a data packet that has already been processed and deleted from memory.

Technologies: [Zephyr Project Zephyr OS](https://junglewise.ai/threats/technologies/zephyr-os). Vendors: [Zephyr Project](https://junglewise.ai/threats/vendors/zephyr-project).

## Quick answers

**Is CVE-2026-10639 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-10639 being exploited in the wild.

**How severe is CVE-2026-10639?** Medium severity, with a CVSS score of 4.8, published 16 June 2026.

**Which products and versions are affected?** Zephyr Project Zephyr OS 1.14.0 to 4.4.0.

**Is there a fix for CVE-2026-10639?** A patch was published on 2026-06-16: Fixed in version 4.5.0 and backported to LTS branches Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-10639 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-10639?** Check whether you run Zephyr Project Zephyr OS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A use-after-free (UAF) vulnerability exists in `subsys/net/ip/icmpv4.c` within the `icmpv4_handle_echo_request()` function. The code hands off an echo-reply packet to the transmission path via `net_try_send_data()`, which transfers ownership and may result in the packet being freed immediately. However, the code subsequently attempts to access the packet's interface pointer to update ICMP statistics. If `CONFIG_NET_STATISTICS_PER_INTERFACE` is enabled, this results in a write-through of a stale or recycled pointer. An unauthenticated remote attacker can trigger this path by sending an ICMPv4 echo request (ping). The vulnerability is subject to a race condition and is fixed in version 4.5.0 by caching the interface pointer before transmission.

## Affected products

- Zephyr Project Zephyr OS 1.14.0 to 4.4.0

## Timeline

- 2019-02-01: other: Vulnerability introduced in version 1.14.0-rc1
- 2026-06-16: disclosed
- 2026-06-16: advisory
- 2026-06-16: patched: Fixed in version 4.5.0 and backported to LTS branches

## References

- [https://github.com/zephyrproject-rtos/zephyr/commit/86e21665d4641f304dc3895bfb03b8f89db83291](https://github.com/zephyrproject-rtos/zephyr/commit/86e21665d4641f304dc3895bfb03b8f89db83291)
- [https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-qhrf-w466-qmpw](https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-qhrf-w466-qmpw)

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