CVE-2025-38478: debian debian_linux Use of Uninitialized Resource

Vulnerability summary

CVE-2025-38478 is a high (CVSS 7.8) Use of Uninitialized Resource vulnerability in debian debian_linux. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7% of scored vulnerabilities.

Timeline

1. 28-07-2025
   PublishedVulnerability first disclosed.
2. 15-10-2026
   Last modifiedVulnerability information updated.

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.

• CWE-908Use of Uninitialized ResourceThe product uses or accesses a resource that has not been initialized.