Vulnerability in Linux kernel (CVE-2026-98087)
Summary
Vulnerability in Linux kernel (CVE-2026-98087). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
sched/rt,dl: Skip migrate-disabled tasks when picking a push candidate
A migrate_disable()'d RT task cannot be moved to another CPU, but the
scheduler still keeps such a task on that CPU's pushable list
(rq->rt.pushable_tasks) and still marks the runqueue RT-overloaded
(rq->rt.overloaded = 1). So the RT balancer keeps treating this CPU as
having a task to move away, and keeps trying to move the task, but the
push can never succeed. When the head is pinned, push_rt_task() does not
give up either. It falls back to pushing rq->curr instead, using the
per-CPU stopper, as added by commit a7c81556ec4d ("sched: Fix
migrate_disable() vs rt/dl balancing").
The CPU spends tens of milliseconds in this retry loop. The core is
isolated for real-time work, but during the loop nearly half of its time
is consumed by pushes that cannot succeed.
An ftrace capture of the affected CPU, with sched_switch enabled and
commit 94894c9c477e ("sched/rt: Skip currently executing CPU in
rto_next_cpu()") applied, shows where the CPU time went. Two SCHED_FIFO
tasks at equal priority shared the CPU, taskA migrate_disable()'d and
queued, taskB as rq->curr. In one 89 ms window, taskB got only 52 ms of
CPU. The other 37 ms went to the stopper thread.
The scheduler kept trying to push taskA, the pinned head of the pushable
list, fell back to pushing taskB instead, and woke the stopper 5204
times. Every one of those pushes failed and no tas…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-98087 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-98087" on the vendor's site.
CVE-2026-98087 (Linux kernel)
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Ubuntu UBUNTU-CVE-2026-98087 linux-hwe-edge
References
- advisory nvd.nist.gov
- advisory github.com
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web github.com