Vulnerability in Linux kernel (CVE-2026-98558)
Summary
Vulnerability in Linux kernel (CVE-2026-98558). 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:
net: flush skb_defer_nodes in dev_cpu_dead()
When a CPU goes offline, dev_cpu_dead() drains its softnet queues
(completion_queue, output_queue, poll_list, process_queue, and
input_pkt_queue), but leaves net_hotdata.skb_defer_nodes untouched.
If oldcpu goes offline while holding pending skbs in its
skb_defer_nodes lists (e.g. below the sysctl_skb_defer_max >> 1 IPI
threshold, or if the IPI races with CPU teardown), those skbs remain
stranded until oldcpu is brought back online. If any of these skbs
hold page_pool fragments, page_pool_destroy() will stall indefinitely
waiting for inflight pages to be returned when a netdev or driver is
torn down while oldcpu is offline.
Additionally, if smp_call_function_single_async() fails in
kick_defer_list_purge() because the target CPU went offline, reset
defer_ipi_scheduled to 0 so future IPI kicks are not blocked when the
CPU comes back online.
Also, if oldcpu was the last online CPU on its NUMA node, drain that
node's slot across all CPUs so no skbs deferred from that node remain
stranded on idle remote CPUs (or if the node itself is subsequently
offlined).
Finally, in skb_attempt_defer_free(), re-check cpu_online(cpu) and
whether the caller migrated CPUs after llist_add(), flushing the node
list if so, to close the preemption TOCTOU race against CPU/node
teardown.
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-2026-98558 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-2026-98558" on the vendor's site.
CVE-2026-98558 (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。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-98558 linux
References
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com