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Fencer Vulns
no cvss —

CVE-2025-68257 json

comedi: check device's attached status in compat ioctls

published 2025-12-16 10 mo ago modified 2026-10-14 26 d ago also EUVD-2025-203740

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

comedi: check device's attached status in compat ioctls

Syzbot identified an issue [1] that crashes kernel, seemingly due to unexistent callback dev->get_valid_routes(). By all means, this should not occur as said callback must always be set to get_zero_valid_routes() in __comedi_device_postconfig().

As the crash seems to appear exclusively in i386 kernels, at least, judging from [1] reports, the blame lies with compat versions of standard IOCTL handlers. Several of them are modified and do not use comedi_unlocked_ioctl(). While functionality of these ioctls essentially copy their original versions, they do not have required sanity check for device's attached status. This, in turn, leads to a possibility of calling select IOCTLs on a device that has not been properly setup, even via COMEDI_DEVCONFIG.

Doing so on unconfigured devices means that several crucial steps are missed, for instance, specifying dev->get_valid_routes() callback.

Fix this somewhat crudely by ensuring device's attached status before performing any ioctls, improving logic consistency between modern and compat functions.

[1] Syzbot report: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... CR2: ffffffffffffffd6 CR3: 000000006c717000 CR4: 0000000000352ef0 Call Trace: <TASK> get_valid_routes drivers/comedi/comedi_fops.c:1322 [inline] parse_insn+0x78c/0x1970 drivers/comedi/comedi_fops.c:1401 do_insnlist_ioctl+0x272/0x700 drivers/comedi/comedi_fops.c:1594 compat_insnlist drivers/comedi/comedi_fops.c:3208 [inline] comedi_compat_ioctl+0x810/0x990 drivers/comedi/comedi_fops.c:3273 __do_compat_sys_ioctl fs/ioctl.c:695 [inline] __se_compat_sys_ioctl fs/ioctl.c:638 [inline] __ia32_compat_sys_ioctl+0x242/0x370 fs/ioctl.c:638 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] ...

Patch / fix

  • Linux Linux 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.62, 6.17.12, 6.18.1, 6.19
  • linux Debian 12 6.1.162-1
  • linux Debian 13 6.12.63-1
  • linux Debian 14 6.17.12-1

debian advisories DEBIAN-CVE-2025-68257

  • linux Ubuntu 22.04 LTS 5.15.0-173.183
  • linux Ubuntu 24.04 LTS 6.8.0-110.110
  • linux Ubuntu 25.10 6.17.0-19.19
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1103.110
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1052.55
  • linux-aws Ubuntu 25.10 6.17.0-1009.9
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1103.112
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1054.57

ubuntu advisories UBUNTU-CVE-2025-68257

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-source Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1
  • kernel-default Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1
  • kernel-kvmsmall Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1
  • kernel-default-base Linux Micro 6.1, Linux Micro 6.0 6.4.0-39.1.21.16
  • kernel-rt Linux Micro 6.2 6.12.0-160000.9.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.9.1

suse advisories SUSE-SU-2026:20845-1SUSE-SU-2026:20876-1SUSE-SU-2026:20477-1SUSE-SU-2026:20498-1SUSE-SU-2026:20207-1SUSE-SU-2026:20220-1

  • kernel-source-longterm openSUSE Tumbleweed 6.18.16-1.1
  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.9.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.9.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.9.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.9.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.9.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.9.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.9.1

opensuse advisories openSUSE-SU-2026:10301-1openSUSE-SU-2026:20145-1openSUSE-SU-2025:15836-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-68257 updated

kernel: comedi: check device's attached status in compat ioctls

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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