CVE-2026-10637: Zephyr OS use-after-free in IPv6 MLD send path

CVE-2026-10637 · Severity: medium · CVSS 5.9 · Published 2026-06-16

A vulnerability exists in the Zephyr operating system's networking stack, specifically within the IPv6 Multicast Listener Discovery (MLD) component. An attacker on the same local network can send a specially crafted network packet that causes the system to access memory it has already released. This can lead to a system crash (denial of service) or, in rare cases, memory corruption, potentially disrupting the device's ability to communicate or operate reliably.

Technologies: Zephyr Project Zephyr OS. Vendors: Zephyr Project.

Quick answers

Is CVE-2026-10637 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-10637 being exploited in the wild.
How severe is CVE-2026-10637?
Medium severity, with a CVSS score of 5.9, published 16 June 2026.
Which products and versions are affected?
Zephyr Project Zephyr OS >= 1.12.0, <= 4.4.0.
Is there a fix for CVE-2026-10637?
A patch was published on 2026-06-16: Fix merged into main branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-10637 attacked?
It is attacked from the adjacent network, in an operating system.
Am I affected by CVE-2026-10637?
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 vulnerability exists in `subsys/net/ip/ipv6_mld.c:mld_send()`. The function calls `net_pkt_iface(pkt)` to update statistics after `net_send_data(pkt)` has already returned successfully. In the Zephyr network stack, a successful send transfers ownership of the packet to the L2 driver, which may immediately free the object. If `CONFIG_NET_STATISTICS_PER_INTERFACE` is enabled, the subsequent access to the freed packet structure results in a dereference of a stale or NULL interface pointer. This is reachable via the `handle_mld_query()` path when the device processes a valid MLDv2 General Query from an adjacent attacker. The flaw is fixed by caching the interface pointer locally before calling the send function.

Affected products

  • Zephyr Project Zephyr OS >= 1.12.0, <= 4.4.0

Timeline

  • 2026-06-16: disclosed
  • 2026-06-16: advisory: GHSA-m23w-34pp-4h92 published
  • 2026-06-16: patched: Fix merged into main branch

References

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