# CVE-2026-10671: User thread can re-initialize an in-use `k_pipe`, corrupting kernel wait queues (`CONFIG_USERSPACE`)

> An unprivileged user thread can corrupt kernel wait queues by re-initializing an active pipe, leading to memory corruption and potential code execution.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Jul 2026
- **Updated:** 15 Oct 2026
- **Also known as:** GHSA-p8w8-3x99-mg8f

## What is CVE-2026-10671?

CVE-2026-10671 is a high-severity memory corruption vulnerability in Zephyrproject Zephyr, published on 14 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In Zephyr's kernel pipe implementation, the userspace syscall verifier z_vrfy_k_pipe_init() in kernel/pipe.c used K_SYSCALL_OBJ() (which requires the kernel object to already be initialized) instead of K_SYSCALL_OBJ_NEVER_INIT() (which rejects an already-initialized object). As a result, on CONFIG_USERSPACE builds an unprivileged user thread that has been granted access to a k_pipe object can invoke the k_pipe_init syscall to re-initialize a pipe that is already in use.

z_impl_k_pipe_init() unconditionally resets the ring buffer, sets pipe->waiting to 0, and re-initializes both wait queues (z_waitq_init on pipe->data and pipe->space) without waking or accounting for threads currently blocked on the pipe. Any thread already pended in k_pipe_read()/k_pipe_write() is left orphaned: still marked pending with pended_on pointing at the cleared wait queue and with stale qnode_dlist links into the (now re-initialized) embedded list head.

When such an orphaned waiter is later timed out or woken, the scheduler calls sys_dlist_remove() on its stale node, writing through dangling prev/next pointers into kernel wait-queue/scheduler structures, causing list corruption (an attacker-driven invalid kernel write), lost wakeups, indefinitely blocked threads, and silent data loss. The flaw lets a deprivileged user thread corrupt the state of a kernel object shared with other threads/partitions.

The fix switches the verifier to K_SYSCALL_OBJ_NEVER_INIT(), matching the existing k_msgq_init verifier, so a user thread can no longer re-initialize a live pipe. The vulnerable code shipped in v4.1.0 and remained through v4.4.0.

Weakness: CWE-1188 (Initialization of a Resource with an Insecure Default), CWE-825 (Expired Pointer Dereference)

## Which versions are affected by CVE-2026-10671?

It affects 1 product.


Products: Zephyrproject Zephyr.

## How do I fix CVE-2026-10671?

No fix has been published for CVE-2026-10671 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-10671 being exploited?

There is no known exploitation of CVE-2026-10671 in the wild and no public exploit code.

## Other vulnerabilities in Zephyrproject Zephyr

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- [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-2026-10671 and fix it if it is affected.

What it is: CVE-2026-10671 is a high-severity memory corruption vulnerability in Zephyrproject Zephyr, published on 14 Jul 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-2026-10671 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-2026-10671/ (Markdown: https://insights.sbomify.com/CVE-2026-10671/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-10671
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-10671
- OSV: https://osv.dev/vulnerability/CVE-2026-10671

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-10671/
Summaries are generated and may contain mistakes; the official description above is the record.