Vulnerability in Linux kernel (CVE-2026-98811)
Summary
Vulnerability in Linux kernel (CVE-2026-98811). 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/sched: cls_api: reclaim an empty proto on the error path
Two racing tc filter add requests on the same chain/prio of an
unlocked classifier both run change() on the shared proto and both
can fail: the winner's tcf_chain_tp_delete_empty() attempt gives up
because the loser's handle is still in the idr, and the loser's
error path drops only its own reference without a second reclamation
attempt. The empty proto stays linked in the chain, holding the
chain reference, a block reference and the classifier module
reference until the chain or block is torn down.
Reclaim the proto on the error path of any failed request that holds
a proto reference. The reclamation is emptiness-gated:
tcf_chain_tp_delete_empty() unlinks the proto only when
delete_empty() admits it is empty, so a live shared proto is never
unlinked. A proto the request created is reclaimed unconditionally -
it is the only owner, so marking it for deletion is safe even without
a delete_empty callback. Classifiers without one (the check marks the
proto unconditionally) are rtnl-serialized, so the raced window this
guard closes cannot arise for them.
This is a follow-up to commit d4e359b3608a ("net/sched: cls_api: fix
teardown of an adopted proto on insert-race loss"), which stopped the
loser of the insert race from unlinking the winner's live proto but
left the empty-proto residual in place.
Conditions to recreate:
- CONFIG_NET_CLS_FLOWER=y; ve…
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-2026-98811 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-2026-98811" on the vendor's site.
CVE-2026-98811 (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-2026-98811 linux
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com