CVE-2025-38480

MEDIUM EPSS 5.3%
Published Jul 28, 202511mo ago · Modified Jun 17, 20262w ago
5.5 CVSS 3.1
Medium
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Published Jul 28, 2025 11mo ago
Last Modified Jun 17, 2026 2w ago

Description

In the Linux kernel, the following vulnerability has been resolved: comedi: Fix use of uninitialized data in insn_rw_emulate_bits() For Comedi `INSN_READ` and `INSN_WRITE` instructions on "digital" subdevices (subdevice types `COMEDI_SUBD_DI`, `COMEDI_SUBD_DO`, and `COMEDI_SUBD_DIO`), it is common for the subdevice driver not to have `insn_read` and `insn_write` handler functions, but to have an `insn_bits` handler function for handling Comedi `INSN_BITS` instructions. In that case, the subdevice's `insn_read` and/or `insn_write` function handler pointers are set to point to the `insn_rw_emulate_bits()` function by `__comedi_device_postconfig()`. For `INSN_WRITE`, `insn_rw_emulate_bits()` currently assumes that the supplied `data[0]` value is a valid copy from user memory. It will at least exist because `do_insnlist_ioctl()` and `do_insn_ioctl()` in "comedi_fops.c" ensure at lease `MIN_SAMPLES` (16) elements are allocated. However, if `insn->n` is 0 (which is allowable for `INSN_READ` and `INSN_WRITE` instructions, then `data[0]` may contain uninitialized data, and certainly contains invalid data, possibly from a different instruction in the array of instructions handled by `do_insnlist_ioctl()`. This will result in an incorrect value being written to the digital output channel (or to the digital input/output channel if configured as an output), and may be reflected in the internal saved state of the channel. Fix it by returning 0 early if `insn->n` is 0, before reaching the code that accesses `data[0]`. Previously, the function always returned 1 on success, but it is supposed to be the number of data samples actually read or written up to `insn->n`, which is 0 in this case.

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
5.3% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-908

Affected Products 14

VendorProductVersionRange
linuxlinux_kernel*≥2.6.29  –  <5.4.297
linuxlinux_kernel*≥5.5  –  <5.10.241
linuxlinux_kernel*≥5.11  –  <5.15.190
linuxlinux_kernel*≥5.16  –  <6.1.147
linuxlinux_kernel*≥6.2  –  <6.6.100
linuxlinux_kernel*≥6.7  –  <6.12.40
linuxlinux_kernel*≥6.13  –  <6.15.8
linuxlinux_kernel6.16any
linuxlinux_kernel6.16any
linuxlinux_kernel6.16any
linuxlinux_kernel6.16any
linuxlinux_kernel6.16any
linuxlinux_kernel6.16any
debiandebian_linux11.0any

References 10

  • git.kernel.org https://git.kernel.org/stable/c/10f9024a8c824a41827fff1fefefb314c98e2c88
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/16256d7efcf7acc9f39abe21522c4c6b77f67c00
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2af1e7d389c2619219171d23f5b96dbcbb7f9656
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/3050d197d6bc9ef128944a70210f42d2430b3000
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/3ab55ffaaf75d0c7b68e332c1cdcc1b0e0044870
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4c2981bf30401adfcdbfece4ab6f411f7c5875a1
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/c53570e62b5b28bdb56bb563190227f8307817a5
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e9cb26291d009243a4478a7ffb37b3a9175bfce9
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
    Third Party Advisory
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
    Third Party Advisory

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/10f9024a8c824a41827fff1fefefb314c98e2c88
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/16256d7efcf7acc9f39abe21522c4c6b77f67c00
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2af1e7d389c2619219171d23f5b96dbcbb7f9656
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/3050d197d6bc9ef128944a70210f42d2430b3000
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/3ab55ffaaf75d0c7b68e332c1cdcc1b0e0044870
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4c2981bf30401adfcdbfece4ab6f411f7c5875a1
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/c53570e62b5b28bdb56bb563190227f8307817a5
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e9cb26291d009243a4478a7ffb37b3a9175bfce9
    Patch