Vulnerability in Linux kernel (CVE-2026-90103)
Summary
Vulnerability in Linux kernel (CVE-2026-90103). 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:
NFSv4.2: fix LAYOUTSTATS send buffer exhaustion
encode_layoutstats_maxsz budgets XDR_QUADLEN(PNFS_LAYOUTSTATS_MAXSIZE),
i.e. 256 bytes, for the layoutupdate4 body written by the layout driver.
The flexfiles record can exceed that.
ff_layout_encode_ff_layoutupdate() emits, per data server, a netaddr4,
an nfs_fh4, two ff_io_latency4, an nfstime4 and a bool. A data server
whose filehandle is NFS_MAXFHSIZE bytes long already accounts for 132 of
those bytes, and the two ff_io_latency4 at 64 bytes each, the nfstime4
and the bool add a further 144, so the body passes 256 bytes before the
netaddr4 is encoded at all. encode_layoutstats() additionally writes
the deviceid4 and the layoutupdate4 lou_type word, neither of which the
macro accounts for.
The filehandle and the address are both chosen by the server, through
LAYOUTGET and GETDEVICEINFO, so it can drive the encoder past the
end of the send buffer. xdr_reserve_space() returns NULL once that
happens, and the two ff_layout_encode_io_latency() calls run with
dss_info->mirror->lock held, so a NULL return there leaves the lock
permanently held.
Raise PNFS_LAYOUTSTATS_MAXSIZE to 384 so that the record fits inside the
reservation.
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-2026-90103 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-90103" on the vendor's site.
CVE-2026-90103 (Linux kernel) — CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
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: High (CVSS 7.5/10). 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-2026-90103 linux Fixed in: 6.1.190-1
- Ubuntu UBUNTU-CVE-2026-90103 linux-aws
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com