[CVE-2026-90290][LOW] arm64: hibernate: Restore DAIF state on error [ Upstream

[CVE-2026-90290][LOW] arm64: hibernate: Restore DAIF state on error [ Upstream

[AL-KERNEL]

CVE: CVE-2026-90290
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: arm64: hibernate: Restore DAIF state on error [ Upstream
Commit: f5693dfaf28d66e7e880feafd1778d3715869efc
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f5693dfaf28d66e7e880feafd1778d3715869efc
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90290
Analysis date: Thu, 17 Sep 2026 17:34:56 -0400
ActionableScore: 0
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-90290 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90290

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: LOW
Manual review required: NO

A detailed explanation of the methodology and priority rules is included
at the end of this message.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-90290	LOW	https://www.kernelcve.org/list/?q=CVE-2026-90290 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:H/UI:N/S:U/C:N/I:N/A:H';CWE-703;CWE-755;*CWE-664;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.1';DESCR 'arm64 hibernation can return from swsusp_arch_suspend with DAIF still masked if swsusp_mte_save_tags fails on the error path. This leaves interrupt and exception masking in an unexpected state after a failed suspend attempt and can cause availability problems such as a hang or severe responsiveness loss. For the CVSS the PR:H is used because triggering hibernation and this failure path is normally limited to an administrator or an equivalent power management service. The issue is local only and is not network reachable. Impact is denial of service only. No memory corruption, information disclosure, or privilege escalation primitive is indicated by the code change.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0)	YES	DANGER SIMPLEFIX ERRORPATH HARDWARE  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	YES	NO	checked

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

ActionableScore=0
PrimitiveClass=NONE
RealUAF=NO
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: 0
* Conservative score: 0
* Raw paranoid score: 0
* Paranoid score: 0
* Final recommended bucket: **Ordinary Moderate**::

No floor or cap changed the score.

2. Signal breakdown

* +1 possible availability impact: returning from `swsusp_arch_suspend()` with DAIF still masked can plausibly cause interrupt handling problems, hang, or severe responsiveness loss after a failed hibernation attempt.
* -2 host admin required: triggering hibernation is normally a host administrator or equivalent power management service operation.
* -1 narrow error path: the issue requires failure of `swsusp_mte_save_tags()` during the arm64 hibernation path, not normal runtime execution.
* No UAF awarded: no freed object, stale reference, refcount misuse, or post-lifetime access is established.
* No memory corruption awarded: the patch restores CPU interrupt-mask state and does not show OOB, UAF, arbitrary write, type confusion, or object lifetime corruption.
* No C/I awarded: no disclosure path or unauthorized modification primitive is established.
* No remote reachability awarded: this is a local hibernation error path.
* No extra availability point awarded: possible hang and responsiveness loss are the same availability consequence.

3. Reachability analysis

The trigger is local and tied to arm64 hibernation. A normal unprivileged user is not shown to be able to invoke the complete vulnerable path. The complete operation is not namespace scoped. The relevant action is system suspend or hibernate, normally mediated by host power management policy or administrator-equivalent service privileges. There is no network path. The issue also depends on the MTE tag saving error path, so the vulnerable state is not expected during ordinary runtime execution.

4. Primitive and severity interpretation

The exact primitive is an invalid CPU exception and interrupt mask state after an error return. This is not active structured stale-object use and not fixed stale storage. There is no concrete repeated release or refcount mutation. PrimitiveClass is NONE because no meaningful corruption, lifetime, ownership, authorization, or security-boundary primitive is established. The demonstrated consequence is availability degradation or possible hang. Privilege escalation and information disclosure are speculative and unsupported. ImportantCandidate is NO because this is a privileged local error-path DoS condition without memory corruption or boundary bypass. AutoDowngradeAllowed is YES because no unresolved Important-grade primitive remains.

5. One-sentence report phrase

An arm64 hibernation error path could return with DAIF still masked after swsusp_mte_save_tags failure, causing local availability impact, but triggering requires host administrator equivalent hibernation control and no memory corruption or privilege escalation primitive is established.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

Reason: the patch shows a narrow privileged hibernation error-path state restoration bug with DoS-only impact and no UAF, corruption, authorization bypass, or network exposure.

7. Call-site confidence

Call-site confidence: medium

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

Patch: arm64: hibernate: Restore DAIF state on error [ Upstream
Commit: f5693dfaf28d66e7e880feafd1778d3715869efc
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f5693dfaf28d66e7e880feafd1778d3715869efc

Changed files:
  arch/arm64/kernel/hibernate.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=f5693dfaf28d66e7e880feafd1778d3715869efc

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

The original Linux kernel CVE announcement for CVE-2026-90290 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90290

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:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.1

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: 0

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: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

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).