# CVE-2025-40070: pps: fix warning in pps_register_cdev when register device fail

> A local attacker can trigger a kernel warning and potential instability in the PPS subsystem by exploiting improper error handling during device registration.

- **Severity:** Not scored
- **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:** Yes
- **Published:** 28 Oct 2025
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2025-40070, DEBIAN-CVE-2025-40070, GHSA-24rq-hg3c-whf7, ROOT-OS-DEBIAN-11-CVE-2025-40070, ROOT-OS-DEBIAN-12-CVE-2025-40070, ROOT-OS-DEBIAN-13-CVE-2025-40070, ROOT-OS-UBUNTU-2204-CVE-2025-40070, ROOT-OS-UBUNTU-2404-CVE-2025-40070, UBUNTU-CVE-2025-40070

## What is CVE-2025-40070?

CVE-2025-40070 is an use after free vulnerability in Linux, published on 28 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

pps: fix warning in pps_register_cdev when register device fail

Similar to previous commit 2a934fdb01db ("media: v4l2-dev: fix error
handling in __video_register_device()"), the release hook should be set
before device_register(). Otherwise, when device_register() return error
and put_device() try to callback the release function, the below warning
may happen.

  ------------[ cut here ]------------
  WARNING: CPU: 1 PID: 4760 at drivers/base/core.c:2567 device_release+0x1bd/0x240 drivers/base/core.c:2567
  Modules linked in:
  CPU: 1 UID: 0 PID: 4760 Comm: syz.4.914 Not tainted 6.17.0-rc3+ #1 NONE
  RIP: 0010:device_release+0x1bd/0x240 drivers/base/core.c:2567
  Call Trace:
   <TASK>
   kobject_cleanup+0x136/0x410 lib/kobject.c:689
   kobject_release lib/kobject.c:720 [inline]
   kref_put include/linux/kref.h:65 [inline]
   kobject_put+0xe9/0x130 lib/kobject.c:737
   put_device+0x24/0x30 drivers/base/core.c:3797
   pps_register_cdev+0x2da/0x370 drivers/pps/pps.c:402
   pps_register_source+0x2f6/0x480 drivers/pps/kapi.c:108
   pps_tty_open+0x190/0x310 drivers/pps/clients/pps-ldisc.c:57
   tty_ldisc_open+0xa7/0x120 drivers/tty/tty_ldisc.c:432
   tty_set_ldisc+0x333/0x780 drivers/tty/tty_ldisc.c:563
   tiocsetd drivers/tty/tty_io.c:2429 [inline]
   tty_ioctl+0x5d1/0x1700 drivers/tty/tty_io.c:2728
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:598 [inline]
   __se_sys_ioctl fs/ioctl.c:584 [inline]
   __x64_sys_ioctl+0x194/0x210 fs/ioctl.c:584
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0x5f/0x2a0 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x76/0x7e
   </TASK>

Before commit c79a39dc8d06 ("pps: Fix a use-after-free"),
pps_register_cdev() call device_create() to create pps->dev, which will
init dev->release to device_create_release(). Now the comment is outdated,
just remove it.

Thanks for the reminder from Calvin Owens, 'kfree_pps' should be removed
in pps_register_source() to avoid a double free in the failure case.

## Which versions are affected by CVE-2025-40070?


## How do I fix CVE-2025-40070?

Apply the vendor's patch.

## Is CVE-2025-40070 being exploited?

There is no known exploitation of CVE-2025-40070 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40070 and fix it if it is affected.

What it is: CVE-2025-40070 is an use after free vulnerability in Linux, published on 28 Oct 2025. 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-2025-40070 in the wild and no public exploit code.

Affected product: Linux. 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-2025-40070/ (Markdown: https://insights.sbomify.com/CVE-2025-40070/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40070
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40070
- OSV: https://osv.dev/vulnerability/CVE-2025-40070

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40070/
Summaries are generated and may contain mistakes; the official description above is the record.