[CVE-2026-98224][LOW] mm/vma: correctly unaccount on mmap_prepare() failure [ Upstream

[CVE-2026-98224][LOW] mm/vma: correctly unaccount on mmap_prepare() failure [ Upstream

[AL-KERNEL]

CVE: CVE-2026-98224
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: mm/vma: correctly unaccount on mmap_prepare() failure [ Upstream
Commit: fb5400bff669c8bad3d4ec09287d9b461e89e5f1
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fb5400bff669c8bad3d4ec09287d9b461e89e5f1
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98224
Analysis date: Fri, 09 Oct 2026 03:18:15 -0400
ActionableScore: 1
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-2026-98224 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98224

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-2026-98224	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98224 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT LOW AEGIS_AS=1 LEGACY=LOW RESULT=SAME (legacy and Aegis reconciliation agree; DECISION: both LOW)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L';*CWE-772;**CWE-400;CWE-404;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '3.3';DESCR 'A failed mmap_prepare() call can leave previously charged committed memory accounted even though the mapping is not created. Repeated failures may inflate the memory commitment counters and cause later memory allocation or mapping requests to fail, resulting in availability degradation. For the CVSS the PR:L is used because a local user process must invoke mmap on an affected file or device and reach the failing callback. The issue is not network reachable. The demonstrated primitive is persistent accounting retention rather than physical memory corruption, so confidentiality and integrity remain unaffected and availability impact is rated Low. Reliable system wide exhaustion depends on an affected mmap_prepare implementation and repeatable attacker control over its failure path.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	MAYBE	READ SIMPLEFIX LINUS MEMORY  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: 1
* Conservative score: 1
* Raw paranoid score: 1
* Paranoid score: 1
* No floor or cap was applied.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 Concrete persistent kernel resource leak. `__mmap_setup()` charges committed memory, but failure of `call_mmap_prepare()` previously bypassed `unacct_error`, leaving the charge without a corresponding mapping or normal cleanup path.
* +0 Resource exhaustion. Repeated leaked charges could eventually cause allocation failures, but the supplied evidence does not establish an attacker-reachable callback that can be made to fail repeatedly or rapid host-wide exhaustion.
* +0 Local unprivileged trigger. Although `mmap()` is available to ordinary processes, access to a file implementing `.mmap_prepare()` and control over its failure path are not established.
* +0 Reliable crash or strong DoS. No panic, Oops, corruption, or immediate system-wide failure is demonstrated.
* +0 B5-R retry-accumulated OOB profile. No heap OOB write, accumulating write offset, corrupted descriptor, or later consumption of corrupted memory exists. The supplied NEW52 profile is inapplicable.
* +0 UAF or repeated lifetime mutation. No object is freed and subsequently used, and no repeated put, release, or refcount operation exists.
* +0 Confidentiality or integrity impact. The defect changes committed-memory accounting only.
* No negative signals were applied because host-admin privilege, rare configuration, or difficult timing is not positively established.

3. Reachability analysis

The initiating system call is local `mmap()`, but the complete trigger requires a file or device whose implementation provides `.mmap_prepare()` and a condition that causes that callback to fail after accounting succeeds. The supplied patch does not identify such a caller, its access permissions, or whether an ordinary user can reliably repeat the failure.

Host-admin-equivalent privilege is therefore not established, but below-host-admin reachability is also not established. No capability namespace, namespace-scoped operation, prior privileged setup, special hardware, boot option, or race is demonstrated. This is an ordered error path rather than a timing race.

4. Primitive and severity interpretation

The exact primitive is a persistent global committed-memory accounting charge left behind after a failed mapping preparation. It is a passive bookkeeping and resource-retention defect, not physical memory corruption.

There is no active structured stale object, fixed stale storage, UAF, OOB access, arbitrary write, repeated release, authorization bypass, or ownership violation. The demonstrated consequence is incorrect accounting. Availability degradation through accumulated false charges is plausible but depends on an unidentified, repeatably failing `.mmap_prepare()` implementation.

`PrimitiveClass=CLASS_C` reflects passive invalid accounting with a possible low-grade DoS consequence. `ImportantCandidate=NO` because no Important-preserving corruption or boundary primitive exists. `AutoDowngradeAllowed=YES` because automatic closure would not discard unresolved memory-corruption or authorization leverage.

5. One-sentence report phrase

A failed mmap_prepare operation can retain an otherwise unused committed-memory charge, potentially causing allocation failures after sufficient repetition, but no memory corruption or reliably attacker-controlled exhaustion path is established.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The patch establishes only a committed-memory accounting leak with no demonstrated OOB write, UAF, strong DoS, security-boundary bypass, or reliable low-privilege accumulation path.

7. Call-site confidence

Call-site confidence: medium

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

Patch: mm/vma: correctly unaccount on mmap_prepare() failure [ Upstream
Commit: fb5400bff669c8bad3d4ec09287d9b461e89e5f1
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fb5400bff669c8bad3d4ec09287d9b461e89e5f1

Changed files:
  mm/vma.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=fb5400bff669c8bad3d4ec09287d9b461e89e5f1

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

The original Linux kernel CVE announcement for CVE-2026-98224 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98224

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:L/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS score: 3.3

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: unknown
  Paranoid ActionableScore: 1

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).