[CVE-2026-90294][MODERATE 7.0] IB/isert: delay the final Login Response until the session is registered [ Upstream

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-90294
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: IB/isert: delay the final Login Response until the session is registered [ Upstream
Commit: e148dbac43308d9e4313070bfc5b355d03134809
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e148dbac43308d9e4313070bfc5b355d03134809
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90294
Analysis date: Fri, 18 Sep 2026 06:07:40 -0400
ActionableScore: 4
ActionableScore lower bound: unknown
Actionable bucket: Borderline / manual review recommended
Manual review required: YES

Summary:
No one-sentence report phrase was found.

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ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-90294 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90294

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-2026-90294	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-90294 CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-362;CWE-665;**CWE-476;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '6.5';DESCR 'An ordering race in the IB isert target path can send the final iSCSI Login Response before the target session is fully registered. A remote RDMA initiator can then send a SCSI command immediately after seeing the successful login response and the command may execute against an se_session whose se_tpg is still NULL, causing a NULL-pointer dereference in target_submit and a kernel crash. For the CVSS the PR:N because the attacker only needs reachability to the exposed iSER target endpoint and does not need local privileges on the victim. The attack is network reachable only on RDMA or storage fabrics, so AV:A is more appropriate than AV:N for most deployments. Impact is denial of service only based on the visible primitive, with no concrete evidence of information disclosure, arbitrary write, or privilege escalation.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 4)	YES	KASAN OOB NULLPTR INIT NETWORK LOG KERNEL_PANIC_PLUS_UAF HARDWARE LINUS TEST KPANIC 	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
======================================================================

ActionableScore=4
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: 4
* Conservative score: 4
* Raw paranoid score: 4
* Paranoid score: 4
* Final recommended bucket: **Borderline / manual review recommended**::

No floor or cap changed the score.

2. Signal breakdown

Positive signals:

* +2 Remote or adjacent network reachable trigger. A remote iSER/RDMA initiator can send a SCSI command immediately after the final Login Response and reach the vulnerable target path.
* +1 Reliable kernel crash / strong DoS. The supplied trace shows a NULL pointer dereference in target_submit from ib-comp-wq.
* +1 Important storage target path. The bug is in the iSER target login-to-command transition and affects command execution against a target session.

Negative signals:

* No negative privilege penalty. The attacker does not need host-admin privileges on the victim once the iSER target endpoint is reachable.
* No race/timing penalty. Although this is an ordering race, the supplied testing shows frequent reproduction, 10 of 20 unpatched runs over rxe, so it is not established as a narrow or externally uncontrollable race.
* No rare-hardware penalty. iSER/RDMA is specialized and often isolated, but the supplied evidence does not prove a rare physical-only requirement.

Important non-awarded signals:

* RealUAF not awarded. The demonstrated primitive is use of an incompletely registered se_session with se_tpg still NULL, not post-free object use.
* Controlled reclaim not demonstrated.
* Arbitrary write not demonstrated.
* Confidentiality and integrity impacts not awarded.
* Strong LPE or strong exploitation leverage not awarded.
* Extra Availability not awarded because the same kernel crash is already counted.
* Concrete repeated release/refcount signal not applicable.
* Structured stale-object leverage not awarded because there is no established stale post-lifetime structured object reuse.

3. Reachability analysis

The evaluated attacker is a remote or adjacent storage-fabric initiator with network reachability to the exposed iSER target. The attacker can trigger the vulnerable ordering by issuing a SCSI command immediately after receiving the final Login Response, before the target session registration has completed.

Host administrator privilege on the victim is not required for the trigger once the target is exposed. Prior administrative setup is required to run an iSER target, but that is ordinary service exposure rather than an attacker privilege requirement. No namespace-scoped privilege model is involved.

The path is not Internet-broad in the usual deployment sense. iSER targets are normally deployed on RDMA or isolated storage networks. The attack surface is therefore adjacent or storage-fabric network exposure rather than a generic public TCP service.

The race is repeatable enough to avoid a hard-race penalty. The supplied test result reports crashes in 10 of 20 unpatched runs over rxe.

4. Primitive and severity interpretation

The exact primitive is a NULL pointer dereference caused by accepting command processing before the iSCSI target session is fully registered. The command can execute against an se_session whose se_tpg is still NULL.

This is not an active structured UAF and not fixed stale storage. It is an ordering or initialization-state violation leading to invalid dereference. There is no concrete repeated release/refcount operation. There is no evidence that the first operation frees an object and a later operation mutates lifetime state through the same dangling reference.

PrimitiveClass is CLASS_C because the demonstrated behavior is crash/DoS through invalid state and NULL dereference without an independently useful corruption primitive.

Demonstrated consequence is kernel crash / denial of service. Speculative consequences such as privilege escalation, information disclosure, or arbitrary kernel memory corruption are not supported by the supplied patch and context.

ImportantCandidate is NO because the patch establishes a remote/adjacent DoS, but not a memory-corruption, ownership, authorization, controlled overwrite, UAF, or boundary-bypass primitive requiring Important preservation.

AutoDowngradeAllowed is YES because no unresolved concrete exploitation primitive beyond crash-only behavior remains established. Manual review is still recommended due to network reachability and storage-target exposure.

Likely operational severity is Borderline / manual review recommended, mainly because this is remotely triggerable on exposed iSER targets but appears to be DoS-only.

5. One-sentence report phrase

An ordering race in the iSER target login path can allow a remote RDMA initiator to send a SCSI command before session registration is complete, causing a NULL pointer dereference in target_submit and a kernel crash.

6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Reason: the issue is network reachable on exposed iSER/RDMA storage targets and has a demonstrated kernel crash, but the established primitive is NULL dereference DoS only and does not show UAF, arbitrary write, information disclosure, or privilege escalation.

7. Call-site confidence

Call-site confidence: high

======================================================================
UPSTREAM PATCH SUMMARY
======================================================================

Patch: IB/isert: delay the final Login Response until the session is registered [ Upstream
Commit: e148dbac43308d9e4313070bfc5b355d03134809
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e148dbac43308d9e4313070bfc5b355d03134809

Changed files:
  drivers/infiniband/ulp/isert/ib_isert.c
  drivers/infiniband/ulp/isert/ib_isert.h

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=e148dbac43308d9e4313070bfc5b355d03134809

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-90294 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90294

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:H/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 6.5

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: 4

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: YES
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 alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).