From: AL-KERNEL <[email protected]>
To: [email protected]
Subject: [CVE-2026-74467][MODERATE 7.0] s390/qeth: Check CAP_NET_ADMIN for private ioctls
Date: Sat, 15 Aug 2026 16:13:23 -0400 [thread overview]
Message-ID: <[email protected]> (raw)
CVE: CVE-2026-74467
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: s390/qeth: Check CAP_NET_ADMIN for private ioctls
Commit: 4e48168825818bf4a13c743582227d15f1d30d04
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4e48168825818bf4a13c743582227d15f1d30d04
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74467
Analysis date: Sat, 15 Aug 2026 16:13:23 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES
Summary:
No one-sentence report phrase was found.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-74467 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74467
The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.
This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.
The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.
Published priority for this report: MODERATE 7.0
Manual review required: YES
A detailed explanation of the methodology and priority rules is included
at the end of this message.
======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================
CVE-2026-74467 MODERATE CHECK WITH IMPACT FROM ORIG NN IMPORTANT Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L';CWE-862;CWE-269;CWE-284;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N';BEST CVSS score: '5.3';DESCR 'qeth private netdevice ioctls lacked a CAP_NET_ADMIN authorization check, allowing a local unprivileged user to invoke adapter specific commands such as SNMP control and adapter information queries. This is an access control bypass in the network device control plane rather than a memory corruption bug. For the CVSS the PR:L because a local unprivileged user or process can reach the ioctl path when a qeth device is present, while the operations should be restricted to network administrators. The issue is not network reachable and cannot be triggered by packet traffic alone. Impact is limited information disclosure and limited integrity impact on qeth adapter control state, with at most low availability impact in the paranoid interpretation.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5) YES SIMPLEFIX NETWORK LINUS LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP YES NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=5
ActionableScoreLower=4
1. ActionableScore
* Conservative score: 4
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**
2. Signal breakdown
* Local unprivileged trigger: +1. The missing check allowed a local unprivileged process to reach qeth private ioctl commands.
* Security-boundary bypass with practical sensitive-object access: +2. The patch restores a CAP_NET_ADMIN boundary around adapter-specific control and query operations.
* Confidentiality impact plausible: +1. SIOC_QETH_GET_CARD_TYPE and SIOC_QETH_QUERY_OAT may expose adapter or network configuration information that should be admin-only.
* Integrity impact plausible: +1. SIOC_QETH_ADP_SET_SNMP_CONTROL can modify qeth adapter control state without the intended capability check.
* Rare hardware / platform-specific exposure: -1. The affected path is specific to IBM s390 qeth devices and is not a broad default subsystem.
* Paranoid availability impact: +1. Unauthorized adapter control could plausibly cause limited operational disruption, but no reliable crash or strong DoS primitive is shown.
3. Reachability analysis
A local user can trigger the issue through SIOCDEVPRIVATE ioctls when a qeth network device is present. It is not reachable by packet traffic alone and is not a remote network parser bug. Namespace impact depends on whether the relevant qeth netdevice is exposed into a container or delegated environment, but the core issue is that operations intended for CAP_NET_ADMIN were reachable without that capability. The affected hardware is platform-specific, so exposure is limited to s390 systems using qeth.
4. Severity interpretation
This is not memory corruption and does not show UAF, OOB access, arbitrary write, or kernel code execution. It behaves as an access-control and capability-boundary bypass in a network device control plane. Conservative handling is borderline/manual-review Moderate. Paranoid handling reaches Actionable Moderate because the exact sensitivity of SNMP control and OAT query behavior should be confirmed on affected deployments.
5. One-sentence report phrase
qeth private netdevice ioctls lacked a CAP_NET_ADMIN check, allowing local unprivileged users to invoke adapter-specific query and control commands, with limited confidentiality and integrity impact and possible limited availability impact on affected s390 qeth systems.
6. Manual review recommendation
MANUAL CHECK REQUIRED. Review should confirm what qeth_snmp_command, SIOC_QETH_GET_CARD_TYPE, and SIOC_QETH_QUERY_OAT can expose or modify on real hardware, because the issue crosses an intended CAP_NET_ADMIN boundary even though no memory corruption primitive is evident.
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: s390/qeth: Check CAP_NET_ADMIN for private ioctls
Commit: 4e48168825818bf4a13c743582227d15f1d30d04
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4e48168825818bf4a13c743582227d15f1d30d04
Commit description:
Gate the SIOCDEVPRIVATE ioctl commands SIOC_QETH_ADP_SET_SNMP_CONTROL,
SIOC_QETH_GET_CARD_TYPE and SIOC_QETH_QUERY_OAT with CAP_NET_ADMIN
capable check to ensure unprivileged users cannot invoke them.
Fixes: 18787ee ("qeth: use ndo_siocdevprivate")
Cc: [email protected]
Suggested-by: Christian Borntraeger <[email protected]>
Reviewed-by: Christian Borntraeger <[email protected]>
Reviewed-by: Alexandra Winter <[email protected]>
Signed-off-by: Aswin Karuvally <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Changed files:
drivers/s390/net/qeth_core_main.c
Diff excerpt:
Not included in this email. See the upstream URL for the full patch.
Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4e48168825818bf4a13c743582227d15f1d30d04
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-74467 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74467
The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.
The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.
This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.
The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.
Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:
Conservative CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
The Best / paranoid CVSS score: 5.3
The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.
CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.
A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.
Conservative ActionableScore: 4
Paranoid ActionableScore: 5
The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.
For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:
ActionableScore below 5 -> MODERATE REGULAR
ActionableScore 5 or more -> MODERATE 7.0
The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.
There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).
KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.
AL-KERNEL base severity for this report: MODERATE
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): MODERATE 7.0
These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).
Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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