CVE-2026-68421
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Don't warn on core-sched forced idle in put_prev_task_scx() put_prev_task_scx() warns when a runnable task drops to a lower sched_class without SCX_OPS_ENQ_LAST, on the assumption that balance_one() would have kept it running. Core scheduling breaks that: a forced-idle SMT sibling reschedules through the core_pick fast path in pick_next_task(), which skips pick_task_scx() and thus balance_one(), so a runnable task can drop to idle with ENQ_LAST unset. Gate the warning on sched_cpu_cookie_match(): a cookie mismatch means core scheduling forced the idle, while a match (or core scheduling off) still catches a genuine missing-ENQ_LAST drop.
Affected versions
Linux kernel versions
6.12
and later are affected. Fixed in
6.18.42,
7.1.6,
7.2
and their respective stable series.
References
3 totalFrequently asked questions
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What is CVE-2026-68421?
CVE-2026-68421 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 6.12 onward and has been patched in 6.18.42, 7.1.6 and 7.2. CVE-2026-68421 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-68421?
Yes. CVE-2026-68421 has been patched. Fixed versions include 6.18.42, 7.1.6 and 7.2. If you are running Linux kernel 6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-68421 actively exploited?
No. CVE-2026-68421 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.