# CVE-2026-10635: Zephyr OS use-after-free in Xtensa MMU page-table management

Source: https://junglewise.ai/threats/cve-2026-10635-zephyr-os-use-after-free-in-xtensa-mmu-page-table-management  
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-2026-10635 · Severity: medium · CVSS 6.3 · Published 2026-06-16

A vulnerability exists in the Zephyr operating system when running on Xtensa processors. The system fails to properly clean up internal memory management records when a memory domain is destroyed, leaving behind 'dangling' references. This can lead to a system crash or, in more complex scenarios, allow memory corruption that could bypass security protections between different applications. Exploiting this requires high-level administrative privileges on the device.

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-2026-10635 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-10635 being exploited in the wild.

**How severe is CVE-2026-10635?** Medium severity, with a CVSS score of 6.3, published 16 June 2026.

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

**Is there a fix for CVE-2026-10635?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-10635 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-10635?** 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 arch/xtensa/core/ptables.c when CONFIG_USERSPACE and CONFIG_XTENSA_MMU are enabled. The function arch_mem_domain_deinit() fails to remove the domain's node from the global xtensa_domain_list before the caller-owned k_mem_domain storage is freed or reused. Subsequent memory mapping operations (arch_mem_map/unmap) traverse this stale list, leading to a NULL pointer dereference or a use-after-free where stale page-table pointers are used for writes. This can result in a denial of service or page-table corruption that undermines userspace isolation. The vulnerability is reachable only via privileged kernel code and was introduced in v4.4.0. It is fixed in the main branch and v4.4-branch by adding sys_slist_find_and_remove() to the deinitialization path.

## Affected products

- Zephyr Project Zephyr OS 4.4.0

## Timeline

- 2026-06-14: other: Embargo date
- 2026-06-16: disclosed: Advisory published by Zephyr Project

## References

- [https://github.com/zephyrproject-rtos/zephyr/commit/33d43d09337119fc6084b4ab545f9267839973f6](https://github.com/zephyrproject-rtos/zephyr/commit/33d43d09337119fc6084b4ab545f9267839973f6)
- [https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-39v7-cx8j-gq82](https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-39v7-cx8j-gq82)

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