Vulnerability in Linux kernel (CVE-2026-98101)
Summary
Vulnerability in Linux kernel (CVE-2026-98101). 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:
ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source()
pmc->sflist is read locklessly under rcu_read_lock() by
inet6_mc_check() during packet reception in the UDP and RAW
multicast receive paths.
ip6_mc_source() mutated psl->sl_addr and psl->sl_count in-place
when adding or removing a source filter. Additionally, when expanding
the filter buffer, newpsl was published via rcu_assign_pointer()
before writing the new source into the array.
Because 16-byte struct in6_addr writes are not atomic and array
shifting is not synchronized with RCU readers, concurrent readers in
inet6_mc_check() could read torn IPv6 addresses or observe
duplicated/missed source entries.
Fix this by switching ip6_mc_source() to copy-on-write RCU updates:
allocate and fully populate newpsl before publishing it via
rcu_assign_pointer(), and reclaim the old filter via kfree_rcu(),
matching ip6_mc_msfilter().
Also remove the now unused IP6_SFBLOCK macro.
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-2026-98101 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-2026-98101" on the vendor's site.
CVE-2026-98101 (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
- Debian DEBIAN-CVE-2026-98101 linux
- Ubuntu UBUNTU-CVE-2026-98101 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 git.kernel.org
- web git.kernel.org
- web github.com