Unscored severity · published Oct 28, 2026
CVE-2026-99104
sched_ext: Fix the bypass dispatch claim for schedulers bypassed by an ancestor
New
–
CVSS
–
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix the bypass dispatch claim for schedulers bypassed by an ancestor scx_bypass() claims bypass dispatch when the scheduler's depth goes from zero to one and releases it when the depth returns to zero, but propagates only the depth to the descendants, not the claim. A descendant that starts bypassing with its ancestor never claims, and one whose own bypass ends under the ancestor's keeps its claim, as its depth does not return to zero. A sub-scheduler enable whose bypass ends under a PM suspend thus leaks its claim: the parent keeps hosting bypass dispatch and the sub-scheduler's next bypass trips the WARN_ON_ONCE() on the claim. A sub-scheduler disable that starts under a PM suspend has no claim, so once the resume lifts the root's bypass its tasks sit on the parent's bypass DSQs with nobody consuming them. Claim for every descendant whose depth goes from zero to one in the propagation and release every scheduler in the subtree whose depth returned to zero once the tasks have moved out of the bypass DSQs. A parent that is bypassing itself when a descendant claims consumes only its own bypass DSQs, empty until it leaves bypass and becomes the host.
Exploitation
Is it being used?
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
aa2a0a19686c90106ade6a7e848ffbb62d55d733 before f0f18075e45d47bef7ff2eb9512ee4f0c7e5f9c7; aa2a0a19686c90106ade6a7e848ffbb62d55d733 before 5bdeca322a6f8d10acaf67cccab1f69747ee7be3; 7.1 · source: vendor
Affected product
LI
Linux
Linux
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