Skip to content
Fencer Intel
high 7.8

CVE-2025-39780 json

sched/ext: Fix invalid task state transitions on class switch

published last yr. modified 21d ago also EUVD-2025-28933

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

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

sched/ext: Fix invalid task state transitions on class switch

When enabling a sched_ext scheduler, we may trigger invalid task state transitions, resulting in warnings like the following (which can be easily reproduced by running the hotplug selftest in a loop):

sched_ext: Invalid task state transition 0 -> 3 for fish[770] WARNING: CPU: 18 PID: 787 at kernel/sched/ext.c:3862 scx_set_task_state+0x7c/0xc0 ... RIP: 0010:scx_set_task_state+0x7c/0xc0 ... Call Trace: <TASK> scx_enable_task+0x11f/0x2e0 switching_to_scx+0x24/0x110 scx_enable.isra.0+0xd14/0x13d0 bpf_struct_ops_link_create+0x136/0x1a0 __sys_bpf+0x1edd/0x2c30 __x64_sys_bpf+0x21/0x30 do_syscall_64+0xbb/0x370 entry_SYSCALL_64_after_hwframe+0x77/0x7f

This happens because we skip initialization for tasks that are already dead (with their usage counter set to zero), but we don't exclude them during the scheduling class transition phase.

Fix this by also skipping dead tasks during class swiching, preventing invalid task state transitions.

Patch / fix

  • Linux Linux 6.12.44, 6.16.4, 6.17
  • linux Debian 13 6.12.48-1
  • linux Debian 14 6.16.5-1

debian advisories DEBIAN-CVE-2025-39780

Is CVE-2025-39780 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

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-2025-39780 updated

kernel: sched/ext: Fix invalid task state transitions on class switch

  • 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

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.