# CVE-2026-10635: Dangling memory-domain pointer (use-after-free) in Xtensa MMU page-table code on memory-domain de-init

> A use-after-free in Zephyr's Xtensa MMU code allows privileged attackers to cause denial of service or memory corruption via dangling pointers.

- **Severity:** Medium 6.3 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Jun 2026
- **Updated:** 15 Oct 2026
- **Also known as:** GHSA-39v7-cx8j-gq82

## What is CVE-2026-10635?

CVE-2026-10635 is a medium-severity use after free vulnerability in Zephyrproject Zephyr, published on 16 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

On Xtensa targets with CONFIG_USERSPACE and CONFIG_XTENSA_MMU, the page-table code (arch/xtensa/core/ptables.c) maintains a global list, xtensa_domain_list, of active memory domains using a list node embedded inside the caller-owned struct k_mem_domain. When a domain is destroyed via k_mem_domain_deinit() -> arch_mem_domain_deinit(), the page tables are torn down and domain->arch.ptables is set to NULL, but the domain's node was not removed from xtensa_domain_list. The freed/deinitialized domain therefore remained linked into the global list as a dangling pointer into caller-owned storage that may then be freed or reused.

Any subsequent arch_mem_map()/arch_mem_unmap() operation (widely invoked by kernel memory-mapping and demand-paging code) traverses the stale node and dereferences domain->ptables: at minimum a NULL pointer dereference causing a fatal MMU exception (denial of service), and if the k_mem_domain storage has been freed or reused, a use-after-free in which a stale/controlled ptables value is dereferenced and written through during the page-table walk (l2_page_table_map writes l1_table[...] and l2_table[...], and xtensa_mmu_compute_domain_regs writes into the domain struct and the L1 table), yielding page-table memory corruption that can undermine userspace isolation.

The vulnerable path is reachable only from privileged kernel/supervisor code (k_mem_domain_deinit is not a syscall), not directly from unprivileged user threads or remotely. Affected: Zephyr v4.4.0 (the Xtensa memory-domain de-initialization feature was introduced in commit 3032b58f52d and first shipped in v4.4.0); fixed on main by adding sys_slist_find_and_remove() in arch_mem_domain_deinit(). The Xtensa MPU path is unaffected.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-10635?

It affects 1 product.


Products: Zephyrproject Zephyr.

## How do I fix CVE-2026-10635?

No fix has been published for CVE-2026-10635 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-10635 being exploited?

There is no known exploitation of CVE-2026-10635 in the wild and no public exploit code.

## Other vulnerabilities in Zephyrproject Zephyr

- [CVE-2026-5067](https://insights.sbomify.com/CVE-2026-5067/): Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key (critical 9.8)
- [CVE-2022-3806](https://insights.sbomify.com/CVE-2022-3806/): Bluetooth HCI Error Handling Double Free (critical 9.8)
- [CVE-2017-14199](https://insights.sbomify.com/CVE-2017-14199/): Memory corruption in getaddrinfo (critical 9.8)
- [CVE-2018-1000800](https://insights.sbomify.com/CVE-2018-1000800/): Null dereference in n/a (critical 9.8)
- [CVE-2021-3329](https://insights.sbomify.com/CVE-2021-3329/): DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer (critical 9.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-10635 and fix it if it is affected.

What it is: CVE-2026-10635 is a medium-severity use after free vulnerability in Zephyrproject Zephyr, published on 16 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-10635 in the wild and no public exploit code.

Affected product: Zephyrproject Zephyr. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-10635/ (Markdown: https://insights.sbomify.com/CVE-2026-10635/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-10635
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-10635
- OSV: https://osv.dev/vulnerability/CVE-2026-10635

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-10635/
Summaries are generated and may contain mistakes; the official description above is the record.