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Fencer Vulns
no cvss —

CVE-2025-40260 json

sched_ext: Fix scx_enable() crash on helper kthread creation failure

published 2025-12-04 11 mo ago modified 2026-10-19 20 d ago also EUVD-2025-201197

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 8%
public exploits
0
none known

Summary

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

sched_ext: Fix scx_enable() crash on helper kthread creation failure

A crash was observed when the sched_ext selftests runner was terminated with Ctrl+\ while test 15 was running:

NIP [c00000000028fa58] scx_enable.constprop.0+0x358/0x12b0 LR [c00000000028fa2c] scx_enable.constprop.0+0x32c/0x12b0 Call Trace: scx_enable.constprop.0+0x32c/0x12b0 (unreliable) bpf_struct_ops_link_create+0x18c/0x22c __sys_bpf+0x23f8/0x3044 sys_bpf+0x2c/0x6c system_call_exception+0x124/0x320 system_call_vectored_common+0x15c/0x2ec

kthread_run_worker() returns an ERR_PTR() on failure rather than NULL, but the current code in scx_alloc_and_add_sched() only checks for a NULL helper. Incase of failure on SIGQUIT, the error is not handled in scx_alloc_and_add_sched() and scx_enable() ends up dereferencing an error pointer.

Error handling is fixed in scx_alloc_and_add_sched() to propagate PTR_ERR() into ret, so that scx_enable() jumps to the existing error path, avoiding random dereference on failure.

Patch / fix

  • Linux Linux 6.17.10, 6.18
  • linux Debian 14 6.17.10-1

debian advisories DEBIAN-CVE-2025-40260

  • linux Ubuntu 25.10 6.17.0-19.19
  • linux-aws Ubuntu 25.10 6.17.0-1009.9
  • linux-gcp Ubuntu 25.10 6.17.0-1009.9
  • linux-azure Ubuntu 25.10 6.17.0-1010.10
  • linux-raspi Ubuntu 25.10 6.17.0-1010.10
  • linux-riscv Ubuntu 25.10 6.17.0-19.19.1
  • linux-oracle Ubuntu 25.10 6.17.0-1009.9
  • linux-aws-6.17 Ubuntu 24.04 LTS 6.17.0-1009.9~24.04.2

ubuntu advisories UBUNTU-CVE-2025-40260

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

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-2025-40260 updated

kernel: sched_ext: Fix scx_enable() crash on helper kthread creation failure

  • 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

0.18% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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