CVE-2025-38478
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-07-28

Last updated on: 2025-11-03

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: comedi: Fix initialization of data for instructions that write to subdevice Some Comedi subdevice instruction handlers are known to access instruction data elements beyond the first `insn->n` elements in some cases. The `do_insn_ioctl()` and `do_insnlist_ioctl()` functions allocate at least `MIN_SAMPLES` (16) data elements to deal with this, but they do not initialize all of that. For Comedi instruction codes that write to the subdevice, the first `insn->n` data elements are copied from user-space, but the remaining elements are left uninitialized. That could be a problem if the subdevice instruction handler reads the uninitialized data. Ensure that the first `MIN_SAMPLES` elements are initialized before calling these instruction handlers, filling the uncopied elements with 0. For `do_insnlist_ioctl()`, the same data buffer elements are used for handling a list of instructions, so ensure the first `MIN_SAMPLES` elements are initialized for each instruction that writes to the subdevice.
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Meta Information
Published
2025-07-28
Last Modified
2025-11-03
Generated
2026-05-07
AI Q&A
2025-07-28
EPSS Evaluated
2026-05-05
NVD
CVE-2025-38478
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
Helpful Resources
Exploitability
CWE
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
How can this vulnerability impact me? :

The impact of this vulnerability could include unpredictable behavior or potential security risks due to the use of uninitialized memory in Comedi subdevice instruction handlers. This might lead to incorrect operation of the device or kernel instability. However, specific impacts such as data leakage or privilege escalation are not detailed.


Can you explain this vulnerability to me?

This vulnerability in the Linux kernel's Comedi subdevice instruction handlers involves uninitialized data usage. Some instruction handlers access data elements beyond the first 'insn->n' elements, but only the first 'insn->n' elements are initialized from user-space data. The remaining elements, up to a minimum of 16 (MIN_SAMPLES), are left uninitialized, which can cause problems if the handler reads these uninitialized elements. The fix ensures that all these elements are initialized, filling any uncopied elements with zero before use.


What immediate steps should I take to mitigate this vulnerability?

The vulnerability is fixed by ensuring that the first MIN_SAMPLES (16) data elements are initialized before calling Comedi subdevice instruction handlers that write to the subdevice, filling any uncopied elements with 0. To mitigate this vulnerability, update the Linux kernel to a version that includes this fix for the Comedi subdevice instruction handlers.


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