High

CVE-2026-80584 — s390/qeth: validate user buffer length in SNMP and ARP query ioctls

In the Linux kernel, the following vulnerability has been resolved: s390/qeth: validate user buffer length in SNMP and ARP query ioctls qeth_snmp_command() and qeth_l3_arp_query() allocate a buffer sized by a user-supplied length (udata_len) without checking a lower bound, then set udata_offset to a fixed non-zero value and pass both to a reply callback. The callback bounds-checks the copy with if ((udata_len - udata_offset) < len) Both fields are u32, so a udata_len smaller than udata_offset makes the subtraction wrap and the check pass, and the following memcpy() writes past the allocation. A udata_len of 0 also yields ZERO_SIZE_PTR from kzalloc(), which the existing NULL check does not catch. Reject buffers smaller than udata_offset before allocating, so the callback subtraction can no longer underflow.

Published Aug 26, 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

8.4

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).
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	≥ 4a71df50047f0db65ea09b1be155852e81a45eba and < 9d00eeb2d27f4cc817c5e408760226d43f811ec6≥ 4a71df50047f0db65ea09b1be155852e81a45eba and < 46443eaddebd84c51940857b11787229be169dec≥ 4a71df50047f0db65ea09b1be155852e81a45eba and < 91935843f9396a9e45253e2c0d4337ca1371754b≥ 4a71df50047f0db65ea09b1be155852e81a45eba and < cc423f4105fe145b33e1d7cad34245a798358f73≥ 4a71df50047f0db65ea09b1be155852e81a45eba and < 3083818e67bcd656965797fbac9a3d6c1d44f78a≥ 4a71df50047f0db65ea09b1be155852e81a45eba and < a3083647747942ea32faf14560d6397ff3068046≥ 4a71df50047f0db65ea09b1be155852e81a45eba and < 75fb3151513d7d9f77a8f9545418279b119c06b8≥ 4a71df50047f0db65ea09b1be155852e81a45eba and < d141f087b1af656f055d7c5793a3e87817ba0bbe and 1 more version 2.6.26	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

Local

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

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
8.4	CVSS 3.1	High	2.5	5.9	416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
8.4	CVSS 3.1	High	—	—	Linux via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.

endpoint telemetry (EDR)

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 · 8.4
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
Aug 26, 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/d141f087b1af656f055d7c5793a3e87817ba0bbe
NIST National Vulnerability Database
git.kernel.org/stable/c/a3083647747942ea32faf14560d6397ff3068046
NIST National Vulnerability Database
git.kernel.org/stable/c/9d00eeb2d27f4cc817c5e408760226d43f811ec6
NIST National Vulnerability Database
git.kernel.org/stable/c/cc423f4105fe145b33e1d7cad34245a798358f73
NIST National Vulnerability Database
git.kernel.org/stable/c/3083818e67bcd656965797fbac9a3d6c1d44f78a
NIST National Vulnerability Database
git.kernel.org/stable/c/91935843f9396a9e45253e2c0d4337ca1371754b
NIST National Vulnerability Database
git.kernel.org/stable/c/75fb3151513d7d9f77a8f9545418279b119c06b8
NIST National Vulnerability Database
git.kernel.org/stable/c/46443eaddebd84c51940857b11787229be169dec
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-2026-80584 is "s390/qeth: validate user buffer length in SNMP and ARP query ioctls", 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 8.4 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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