CVE-2025-38478: Debian Linux

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: from 2.6.29, before 5.4.297 (fixed in 5.4.297); from 5.5, before 5.10.241 (fixed in 5.10.241); from 5.11, before 5.15.190 (fixed in 5.15.190); from 5.16, before 6.1.147 (fixed in 6.1.147); from 6.2, before 6.6.100 (fixed in 6.6.100); from 6.7, before 6.12.40 (fixed in 6.12.40); …

Published 2025-07-28. Last modified 2026-07-30.