Vulnerability in Linux kernel (CVE-2026-89698)
Summary
Vulnerability in Linux kernel (CVE-2026-89698). 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:
nfsd: widen nfsd_genl_rqstp address fields to sockaddr_storage
struct nfsd_genl_rqstp declares rq_daddr and rq_saddr as plain
"struct sockaddr" (16 bytes). When an IPv6 NFS client is connected,
nfsd_genl_rpc_status_compose_msg() casts these fields to
"struct sockaddr_in6 *" (28 bytes) and reads sin6_addr at offset 8..24,
which extends 8 bytes past the end of the 16-byte sockaddr field into
the adjacent rq_flags member. The 16-byte nla_put_in6_addr then ships 8
bytes of truncated IPv6 address followed by 8 bytes of rq_flags to
userspace via the NFSD_A_RPC_STATUS_SADDR6/DADDR6 netlink attributes.
This is reachable by any unprivileged process in the network namespace
because NFSD_CMD_RPC_STATUS_GET uses GENL_CMD_CAP_DUMP without
GENL_ADMIN_PERM.
Fix by widening rq_daddr and rq_saddr to struct sockaddr_storage so the
IPv6 casts operate within bounds, copying sizeof(struct sockaddr_storage)
bytes in the memcpy calls so the full address is captured, and
zero-initializing the genl_rqstp stack variable to prevent leaking
uninitialized tail bytes through netlink.
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-2026-89698 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-2026-89698" on the vendor's site.
CVE-2026-89698 (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-2026-89698 linux Fixed in: 6.12.111-1
- Ubuntu UBUNTU-CVE-2026-89698 linux-hwe-edge
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com