* [CVE-2026-90007][MODERATE REGULAR] scsi: pm8001: Use rollback index when freeing MSI-X vectors
@ 2026-09-16 17:37 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-16 17:37 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-90007
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: scsi: pm8001: Use rollback index when freeing MSI-X vectors
Commit: f39e3ca1f688d7c08954a0794e9bf1e279c83b15
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f39e3ca1f688d7c08954a0794e9bf1e279c83b15
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90007
Analysis date: Wed, 16 Sep 2026 13:37:52 -0400
ActionableScore: 4
ActionableScore lower bound: 3
Actionable bucket: Borderline / manual review recommended
Manual review required: YES
Summary:
Incorrect rollback cleanup in pm8001 MSI-X setup can leave previously registered IRQ handlers installed after request_irq failure, creating a local stale handler and DoS risk if later cleanup invalidates the associated driver state.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90007 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90007
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-2026-90007 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-90007 CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';CWE-404;*CWE-772;*CWE-416;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.8';DESCR 'pm8001_request_msix has incorrect rollback cleanup when request_irq fails during MSI-X setup. The loop uses the failing vector index for every free_irq call instead of the already registered rollback index, so earlier interrupt handlers can remain installed with stale device context after initialization fails. For the CVSS the PR:L is used for the paranoid score because a reduced capability root, service account, or delegated admin that can reload the PCI driver or trigger driver probe paths may be enough in some deployments, although the normal base case is PR:H. The issue is local and not network reachable. Impact is at least denial of service through leaked IRQ handlers or later crashes, and in worst case may allow limited confidentiality or integrity impact if a stale handler dereferences freed driver state.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 4) YES SIMPLEFIX HARDWARE LINUS INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=4
ActionableScoreLower=3
PrimitiveClass=CLASS_B
RealUAF=NO
HostAdminRequired=UNKNOWN
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: 4
* Paranoid score: 4. No floor or cap applied.
* Final recommended bucket: **Borderline / manual review recommended**::
## 2. Signal breakdown
Conservative signals:
* +1 Concrete persistent kernel resource/reference leak. The rollback path uses the failing MSI-X index `i` instead of the already registered index `j`, so previously installed IRQ handlers are not freed.
* +1 Active-state retirement bypass. `free_irq()` is the required retirement operation for active IRQ handler registrations, and the bug skips the correct unregister operation for live handlers.
* +1 Reliable DoS plausibility. Leaving IRQ handlers installed after failed initialization can plausibly lead to later invalid interrupt handling, WARN/Oops, or driver cleanup breakage.
Paranoid additional signal:
* +1 Stale callback/lifetime concern. The remaining IRQ handlers may retain `dev_id` pointers into driver state after the probe failure path continues, so a stale handler callback risk remains unresolved.
Non-awarded signals:
* Controlled reclaim not demonstrated.
* Arbitrary or directed kernel write not demonstrated.
* RealUAF not marked YES because the patch establishes leaked IRQ handlers, but does not directly show a later post-free handler invocation.
* Concrete repeated release/refcount signal not awarded. The loop incorrectly calls `free_irq()` for the failed index `i`, but this is not a proven second lifetime mutation on an exact dangling reference after a first release may have freed it.
* Structured stale-object leverage not separately awarded because no distinct post-reuse field consumption is shown.
* C/I impact not awarded because the evidence supports DoS and stale callback concern, not disclosure or integrity modification.
* Remote reachability not established.
* No race/timing penalty applied. This is an ordered rollback bug, not a demonstrated hard race.
## 3. Reachability analysis
The vulnerable code is in the pm8001 SCSI driver MSI-X setup error path. A realistic trigger requires `request_irq()` to fail after earlier IRQ handlers were already registered. That normally occurs during driver probe, load, bind, or device initialization failure handling.
Host-admin-equivalent control is plausible because driver loading, binding, PCI device management, or fault injection is typically privileged, but the supplied evidence does not fully prove that every practical trigger requires host admin. Therefore `HostAdminRequired=UNKNOWN`, not YES.
The operation is not namespace-scoped. No network namespace, user namespace, or delegated namespace capability path is established.
No direct network reachability is shown. Hardware or device interrupt behavior may influence the later stale handler path, but the patch does not establish a remote attacker path.
Special hardware is involved, but no separate rare-hardware penalty is applied solely because this is a driver.
## 4. Primitive and severity interpretation
The exact primitive is incorrect rollback cleanup of MSI-X IRQ handlers. The code should free registered vectors `0..i-1`, but instead repeatedly uses the failing index `i`, leaving earlier handlers installed.
This is best treated as a Class B active-state lifetime/resource-retirement bug, not as proven Class A corruption. The active kernel object is an IRQ handler registration with a `dev_id` pointing into driver-owned state. If the failed initialization path later releases or invalidates that state, a remaining IRQ handler could become a stale callback path.
This is not a confirmed RealUAF from the supplied patch alone because the later freeing of the driver state and subsequent interrupt invocation are not shown in the diff. It is also not a concrete repeated release/refcount case, because the visible bug is failure to free the correct handlers rather than a proven second put/free on the same dangling object.
Demonstrated consequence is incorrect cleanup and persistent active handler registration. Practical consequence is likely DoS or kernel instability. Privilege escalation is not supported by the patch. ImportantCandidate is NO because no controlled reclaim, arbitrary write, callback control from attacker-shaped memory, or confirmed UAF exploitation primitive is established. AutoDowngradeAllowed is YES, but manual review is recommended because stale IRQ handler registration can hide a real post-teardown callback bug depending on the surrounding cleanup path.
Likely operational severity: borderline Moderate, with manual review useful to confirm whether failed probe cleanup can free `pm8001_ha` or `irq_vector[]` while handlers remain registered.
## 5. One-sentence report phrase
Incorrect rollback cleanup in pm8001 MSI-X setup can leave previously registered IRQ handlers installed after request_irq failure, creating a local stale handler and DoS risk if later cleanup invalidates the associated driver state.
## 6. Manual review recommendation
MANUAL CHECK RECOMMENDED
Review the full probe failure and cleanup path to determine whether `pm8001_ha` or `irq_vector[]` can be freed while the earlier IRQ handlers remain registered, and whether device interrupts can invoke those stale handlers.
## 7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: scsi: pm8001: Use rollback index when freeing MSI-X vectors
Commit: f39e3ca1f688d7c08954a0794e9bf1e279c83b15
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f39e3ca1f688d7c08954a0794e9bf1e279c83b15
Commit description:
pm8001_request_msix() unwinds previously registered handlers with
free_irq() when request_irq() fails. The rollback loop uses the failing
index i for every iteration instead of the already registered vector
index j.
That passes the wrong IRQ/dev_id pair to free_irq() and leaves the
earlier handlers installed. Use j for both pci_irq_vector() and the
matching irq_vector entry in the rollback loop.
Fixes: a76037f ("scsi: pm8001: switch to pci_irq_alloc_vectors")
Cc: [email protected]
Assisted-by: Codex:GPT-5
Signed-off-by: Runyu Xiao <[email protected]>
Acked-by: Jack Wang <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Martin K. Petersen (Oracle) <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Changed files:
drivers/scsi/pm8001/pm8001_init.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=f39e3ca1f688d7c08954a0794e9bf1e279c83b15
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90007 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90007
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:H/PR:H/UI:N/S:U/C:N/I:N/A:H
The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
The Best / paranoid CVSS score: 5.8
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: 3
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: 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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