CVE-2025-38687
What it is
In the Linux kernel, the following vulnerability has been resolved: comedi: fix race between polling and detaching syzbot reports a use-after-free in comedi in the below link, which is due to comedi gladly removing the allocated async area even though poll requests are still active on the wait_queue_head inside of it. This can cause a use-after-free when the poll entries are later triggered or removed, as the memory for the wait_queue_head has been freed. We need to check there are no tasks queued on any of the subdevices' wait queues before allowing the device to be detached by the `COMEDI_DEVCONFIG` ioctl. Tasks will read-lock `dev->attach_lock` before adding themselves to the subdevice wait queue, so fix the problem in the `COMEDI_DEVCONFIG` ioctl handler by write-locking `dev->attach_lock` before checking that all of the subdevices are safe to be deleted. This includes testing for any sleepers on the subdevices' wait queues. It remains locked until the device has been detached. This requires the `comedi_device_detach()` function to be refactored slightly, moving the bulk of it into new function `comedi_device_detach_locked()`. Note that the refactor of `comedi_device_detach()` results in `comedi_device_cancel_all()` now being called while `dev->attach_lock` is write-locked, which wasn't the case previously, but that does not matter. Thanks to Jens Axboe for diagnosing the problem and co-developing this patch.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account, but needs a user to act. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.1% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.1% in the next 30 days (EPSS).
- Severity: 7.3 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.1% · EPSS, next 30 days
- Weakness
- CWE-362 · Race condition
- Record status
- Modified
Affected
- Linux Kernel < 5.4.297
- Linux Kernel < 5.10.241
- Linux Kernel < 5.15.190
- Linux Kernel < 6.1.149
- Linux Kernel < 6.6.103
- Linux Kernel < 6.12.43
- Linux Kernel < 6.15.11
- Linux Kernel < 6.16.2
Attack profile CVSS 3.1 · 7.3
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2025-38687.md and follow it. Check whether this project is affected by CVE-2025-38687. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/017198079551a2a5cf61eae966af3c4b145e1f3b
- https://git.kernel.org/stable/c/0f989f9d05492028afd2bded4b42023c57d8a76e
- https://git.kernel.org/stable/c/35b6fc51c666fc96355be5cd633ed0fe4ccf68b2
- https://git.kernel.org/stable/c/5724e82df4f9a4be62908362c97d522d25de75dd
- https://git.kernel.org/stable/c/5c4a2ffcbd052c69bbf4680677d4c4eaa5a252d4
- https://git.kernel.org/stable/c/71ca60d2e631cf9c63bcbc7017961c61ff04e419
- https://git.kernel.org/stable/c/cd4286123d6948ff638ea9cd5818ae4796d5d252
- https://git.kernel.org/stable/c/d85fac8729c9acfd72368faff1d576ec585e5c8f
- https://git.kernel.org/stable/c/fe67122ba781df44a1a9716eb1dfd751321ab512
References
- https://git.kernel.org/stable/c/017198079551a2a5cf61eae966af3c4b145e1f3b
- https://git.kernel.org/stable/c/0f989f9d05492028afd2bded4b42023c57d8a76e
- https://git.kernel.org/stable/c/35b6fc51c666fc96355be5cd633ed0fe4ccf68b2
- https://git.kernel.org/stable/c/5724e82df4f9a4be62908362c97d522d25de75dd
- https://git.kernel.org/stable/c/5c4a2ffcbd052c69bbf4680677d4c4eaa5a252d4
- https://git.kernel.org/stable/c/71ca60d2e631cf9c63bcbc7017961c61ff04e419
- https://git.kernel.org/stable/c/cd4286123d6948ff638ea9cd5818ae4796d5d252
- https://git.kernel.org/stable/c/d85fac8729c9acfd72368faff1d576ec585e5c8f
- https://git.kernel.org/stable/c/fe67122ba781df44a1a9716eb1dfd751321ab512
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html