High

CVE-2026-90103 — NFSv4.2: fix LAYOUTSTATS send buffer exhaustion

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.

Published Sep 17, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Linux

CVSS base

7.5

High · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ 27c430644369ccd9a2272492ba6d0e85e2e4800b and < 842ac26615424577f24f0486b9d3bf97f28fad9c≥ 27c430644369ccd9a2272492ba6d0e85e2e4800b and < 397aa7000bbf6b6a0d32e66a544e978fb478c8e4≥ 27c430644369ccd9a2272492ba6d0e85e2e4800b and < e82d7d999fe9f893f84bf332fd39cb5d9de7128f≥ 27c430644369ccd9a2272492ba6d0e85e2e4800b and < 5aca000630c0fd0da102ae1abf9245dd74f2ce36≥ 27c430644369ccd9a2272492ba6d0e85e2e4800b and < cb11590c7ddc6883a1b1d70b1f98b2779fe626f2≥ 27c430644369ccd9a2272492ba6d0e85e2e4800b and < 3815b894b922e9b4f40b8b6f6d67bf80d44141c9≥ 27c430644369ccd9a2272492ba6d0e85e2e4800b and < a973622da0c62c34043ddbbf382cd761b03e5136≥ 27c430644369ccd9a2272492ba6d0e85e2e4800b and < c75ef2137e749f2673f0617cfdaae53b2bb7195a and 1 more version 4.2	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.5	CVSS 3.1	High	3.9	3.6	416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
7.5	CVSS 3.1	High	—	—	Linux via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 7.5
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Received
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 17, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

8 on the record

git.kernel.org/stable/c/cb11590c7ddc6883a1b1d70b1f98b2779fe626f2
NIST National Vulnerability Database
git.kernel.org/stable/c/a973622da0c62c34043ddbbf382cd761b03e5136
NIST National Vulnerability Database
git.kernel.org/stable/c/c75ef2137e749f2673f0617cfdaae53b2bb7195a
NIST National Vulnerability Database
git.kernel.org/stable/c/5aca000630c0fd0da102ae1abf9245dd74f2ce36
NIST National Vulnerability Database
git.kernel.org/stable/c/e82d7d999fe9f893f84bf332fd39cb5d9de7128f
NIST National Vulnerability Database
git.kernel.org/stable/c/397aa7000bbf6b6a0d32e66a544e978fb478c8e4
NIST National Vulnerability Database
git.kernel.org/stable/c/842ac26615424577f24f0486b9d3bf97f28fad9c
NIST National Vulnerability Database
git.kernel.org/stable/c/3815b894b922e9b4f40b8b6f6d67bf80d44141c9
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 14h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 14h
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-90103 is "NFSv4.2: fix LAYOUTSTATS send buffer exhaustion", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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