* [CVE-2026-90293][MODERATE REGULAR] IB/isert: post the full-feature receive buffers after session registration [ Upstream
@ 2026-09-17 22:59 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-17 22:59 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-90293
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: IB/isert: post the full-feature receive buffers after session registration [ Upstream
Commit: 962edb9a6b0dae09d33a677485a398fc7d55968c
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=962edb9a6b0dae09d33a677485a398fc7d55968c
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90293
Analysis date: Thu, 17 Sep 2026 18:59:44 -0400
ActionableScore: 3
ActionableScore lower bound: unknown
Actionable bucket: Borderline / manual review recommended
Manual review required: YES
Summary:
No one-sentence report phrase was found.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90293 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90293
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 REGULAR
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-2026-90293 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-90293 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-362;**CWE-476;CWE-754;Other CVSS 'AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7.5';DESCR 'An iSER target session ordering bug allows full feature receive buffers to be posted before __transport_register_session() has completed. A malicious or non compliant initiator can send a SCSI command before waiting for the final Login Response, so the command may reach target_submit() while se_session.se_tpg is still NULL, causing a kernel oops and denial of service. For the CVSS the PR:N is used because a remote initiator generally needs only network access to the iSER target and no local account on the victim, although real deployments may restrict initiators by storage fabric policy or authentication. The issue is network reachable over RDMA based iSER, mostly in InfiniBand, RoCE, or iWARP storage networks rather than the public Internet. Impact is denial of service via kernel crash. No concrete information disclosure, arbitrary write, or privilege escalation primitive is shown by this patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 3) YES LOCK NETWORK LOG TIMER LINUS TEST INCREASED_TO_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=3
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 3
* Conservative score: 3. No floor or cap applied.
* Raw paranoid score: 3
* Paranoid score: 3. No floor or cap applied.
* Final recommended bucket: **Borderline / manual review recommended**::
2. Signal breakdown
Positive signals:
* +2 Remote reachable / directly network-triggerable: a remote iSER initiator can send an early SCSI command before waiting for the final Login Response and reach the vulnerable target path.
* +1 Reliable kernel crash / strong DoS: the commit directly reports kernel oops at target_submit when se_session.se_tpg is NULL.
Negative signals:
* 0 No host-admin penalty: attacker does not need local host-admin privileges on the target, only reachability as an iSER initiator.
* 0 No race/timing penalty: this is mainly an ordering/protocol-state bug. The early send can be deliberately attempted, and reported testing showed frequent oopses on unpatched builds.
* 0 No rare-hardware penalty: iSER/RDMA is specialized, but the evidence includes rxe testing and common RDMA storage deployments. Specialized subsystem alone is not enough for a penalty.
Important non-awarded signals:
* RealUAF not awarded: the established primitive is NULL se_tpg dereference, not use-after-free.
* Controlled reclaim not demonstrated.
* Arbitrary write not demonstrated.
* Confidentiality and integrity not awarded.
* Extra availability not awarded because the same kernel oops is already counted as reliable DoS.
* Concrete repeated release/refcount not present.
* Structured stale-object leverage not awarded because no stale post-lifetime object reuse is established.
* Strong LPE or privilege escalation not awarded.
3. Reachability analysis
The attacker is a remote iSER initiator with network or fabric access to the iSER target. No local account on the victim host is required, so HostAdminRequired=NO.
The trigger is not namespace-scoped and does not depend on attacker-created Linux namespaces. NamespaceScopedPrivilege=NO.
Prior target configuration is required in the normal sense that the victim must be running an iSER target, but that is the exposed service being attacked, not an attacker prerequisite requiring host-admin access.
The attack is relevant mainly to RDMA storage fabrics such as InfiniBand, RoCE, or iWARP. It is typically not public Internet exposure, but it is still externally reachable within storage or data-center networks.
The bug is not a hard race in the scoring sense. It depends on the initiator violating expected ordering by sending before the final Login Response, but this behavior is attacker-controllable.
4. Primitive and severity interpretation
The exact primitive is invalid state leading to NULL pointer dereference: an early SCSI command can be processed against an se_session where se_tpg is still NULL.
This is not active structured UAF and not fixed stale storage. It is a protocol/session registration ordering flaw causing a crash.
PrimitiveClass=CLASS_C because demonstrated behavior is crash/DoS through NULL dereference without an independently useful corruption primitive.
Demonstrated consequence: kernel oops / denial of service.
Speculative consequence: stronger exploitation is not supported by the supplied patch context.
ImportantCandidate=NO because there is no UAF, no repeated lifetime mutation, no controlled overwrite, no authorization bypass, and no demonstrated C/I impact.
AutoDowngradeAllowed=YES because the issue is a network-reachable crash-only Class C bug without unresolved memory-corruption or security-boundary leverage. Manual review is still recommended due to remote/fabric reachability and kernel crash.
Likely operational severity: high CVSS-style availability impact in exposed iSER target deployments, but ActionableScore remains borderline because the primitive is DoS-only.
5. One-sentence report phrase
A remote or fabric-reachable iSER initiator can send a SCSI command before the final Login Response and cause target_submit to dereference a NULL se_tpg, leading to a kernel crash and denial of service.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
Reason: network/fabric reachability and a reliable kernel oops justify review, but no UAF, memory corruption, privilege escalation, authorization bypass, or C/I primitive is established.
7. Call-site confidence
Call-site confidence: high
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: IB/isert: post the full-feature receive buffers after session registration [ Upstream
Commit: 962edb9a6b0dae09d33a677485a398fc7d55968c
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=962edb9a6b0dae09d33a677485a398fc7d55968c
Changed files:
drivers/infiniband/ulp/isert/ib_isert.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=962edb9a6b0dae09d33a677485a398fc7d55968c
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90293 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90293
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:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
The Best / paranoid CVSS vector: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
The Best / paranoid CVSS score: 7.5
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: unknown
Paranoid ActionableScore: 3
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 REGULAR
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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