Vulnerability in Linux kernel (CVE-2026-89517)
Summary
Vulnerability in Linux kernel (CVE-2026-89517). 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_ext: Fix rq->core_pick corruption under core scheduling
Core scheduling's pick_next_task() picks what to run on every SMT sibling of
the core in a single pass under the shared core-wide rq lock. The selection
state is consistent only while the lock is held continuously, so
->pick_task() originally could not release it. However, since 4c95380701f5
("sched/ext: Fold balance_scx() into pick_task_scx()"), sched_ext runs
dispatch from inside the pick and dispatching can drop the rq lock. To
support this, pick_next_task() has been updated to restart the whole
selection when a pick returns RETRY_TASK after releasing the lock.
When selections on the same core interleave through the dropped lock, they
corrupt each other's state: one clears the other's rq->core_pick leading to
a NULL deref, or invalidates its keep-the-previous-task decision leaving a
dequeued task running, which deadlocks the next wakeup and matches the
reported hard hangs. A cookied ping-pong load on an SMT machine makes the
interleavings frequent and kills the kernel within seconds.
Fix it by making the pick return RETRY_TASK whenever dispatch released the
rq lock, so that a selection only ever commits picks made under a
continuously held lock. The previous patch's rq->scx.lock_drop_seq counts
the releases. A dispatch that touched nothing never releases the lock and
its verdict, including "nothing to run", stands: retries are bounded, each…
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-2026-89517 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-2026-89517" on the vendor's site.
CVE-2026-89517 (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。
References
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com