[CVE-2026-97544][LOW] xfs: don't leak dqacct if rhashtable insertion fails

[CVE-2026-97544][LOW] xfs: don't leak dqacct if rhashtable insertion fails

[AL-KERNEL]

CVE: CVE-2026-97544
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: xfs: don't leak dqacct if rhashtable insertion fails
Commit: 9036e078bd51683e862afd5ed25ecba2f780b165
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9036e078bd51683e862afd5ed25ecba2f780b165
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97544
Analysis date: Fri, 25 Sep 2026 11:20:00 -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-2026-97544 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97544

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-2026-97544	LOW	https://www.kernelcve.org/list/?q=CVE-2026-97544 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-401;*CWE-772;**CWE-400;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.1';DESCR 'A memory leak in XFS live quotacheck occurs when xqcheck_mod_live_ino_dqtrx allocates a quota accounting object and rhashtable_insert_fast fails. The allocated object is then abandoned on the error path. Repeated failures during quota checking could consume kernel memory and eventually cause resource exhaustion or denial of service. For the CVSS the PR:H reflects that live XFS quotacheck and filesystem maintenance operations are normally restricted to an administrator or a privileged maintenance service. The issue is not network reachable. No confidentiality or integrity impact is supported because the patch shows a resource leak only and no memory corruption primitive.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	YES	DISK SIMPLEFIX LEAK LINUS 	YES	NO	checked

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

ActionableScore=1
PrimitiveClass=NONE
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
* Final recommended bucket: **Ordinary Moderate**::

The supplied patch establishes a small kernel memory leak only. There is no supported basis for a paranoid increase because repeated attacker-controlled triggering, host-wide exhaustion, cross-namespace impact, or a security-boundary bypass is not established.

2. Signal breakdown

* +1 Concrete persistent kernel resource leak. `dqa` is allocated and becomes unreachable if `rhashtable_insert_fast()` fails, because the previous error path jumps to `out_abort` without freeing it.
* +0 Resource exhaustion. The leak could accumulate if the failing operation is repeatedly reached, but the supplied evidence does not establish reliable repetition, attacker control of insertion failure, significant per-operation allocation volume, or host-wide memory exhaustion.
* +0 Reliable kernel crash or strong DoS. No crash, filesystem shutdown, assertion, or immediate availability failure is shown.
* +0 Confidentiality impact. No disclosure or read-back primitive is established.
* +0 Integrity impact. No memory corruption, metadata corruption, unauthorized modification, or ownership violation is established.
* +0 Remote reachability. The path is not network reachable from the supplied evidence.
* +0 Local unprivileged trigger. The patch does not establish that an ordinary user can invoke live XFS quotacheck or reliably induce the rhashtable insertion failure.
* +0 Filesystem metadata corruption. The bug leaks an accounting object but does not corrupt XFS metadata or file contents.
* No negative privilege penalty was applied. The supplied hint says PR:H is typical, but it does not provide visible call-site or capability-check evidence sufficient to positively establish host-admin-equivalent privilege under the requested rules.

3. Reachability analysis

The affected function is in XFS live quotacheck handling and is reached while tracking quota updates. The patch establishes only that a failed insertion into `shadow_dquot_acct` leaks the newly allocated `dqa` object.

The complete triggering chain is not visible. In particular, the supplied material does not show which ioctl, scrub, repair, mount operation, or kernel-internal workflow starts live quotacheck, nor does it show the capability checks governing that operation. Therefore HostAdminRequired is `UNKNOWN`, not `YES`.

There is no evidence that an ordinary local user can create the required XFS state, initiate live quotacheck, repeatedly cause insertion failure, or amplify this into meaningful memory exhaustion. There is also no namespace evidence showing that the complete operation is available with namespace-scoped privileges. NamespaceScopedPrivilege is therefore `UNKNOWN`.

No network input, special hardware, boot configuration, sysctl prerequisite, race, UAF, or attacker-controlled payload is involved in the demonstrated defect.

4. Primitive and severity interpretation

The exact primitive is a missing `kfree(dqa)` on a failure path after `rhashtable_insert_fast()` returns an error. This is a concrete memory/resource leak.

There is no stale-object use after lifetime end, no second release, no refcount mutation through freed storage, no double free, no RCU lifetime mismatch, and no active structured-object reuse. Therefore RealUAF is `NO` and PrimitiveClass is `NONE`.

The demonstrated consequence is bounded kernel memory leakage per failed insertion attempt. A larger denial-of-service consequence through sustained accumulation is possible in principle, but it is not established by the patch because reliable repeated triggering and attacker reachability are not shown.

ImportantCandidate is `NO` because no corruption, authorization, ownership, COW, metadata-integrity, or security-boundary primitive exists. AutoDowngradeAllowed is `YES` because this is a resource-leak-only fix with no unresolved exploitation primitive.

Likely operational severity is Low or ordinary Moderate depending on whether the affected deployment actively uses live XFS quotacheck and can repeatedly encounter the error path.

5. One-sentence report phrase

A failed rhashtable insertion during XFS live quotacheck leaked a newly allocated quota accounting object, potentially causing resource exhaustion only if the failing path can be repeatedly invoked.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The patch demonstrates a missing free on an error path only. No memory corruption, privilege escalation, protected-data access, integrity impact, or attacker-controlled repeatability is established.

7. Call-site confidence

Call-site confidence: medium

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

Patch: xfs: don't leak dqacct if rhashtable insertion fails
Commit: 9036e078bd51683e862afd5ed25ecba2f780b165
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9036e078bd51683e862afd5ed25ecba2f780b165

Commit description:

LOLLM observes that xqcheck_mod_live_ino_dqtrx doesn't free the newly
allocated dqa object if rhashtable insertion fails.  Fix this leak.

Cc: stable@vger.kernel.org # v6.9
Fixes: 2004918 ("xfs: track quota updates during live quotacheck")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Assisted-by: LOLLM # finding obvious bugs
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  fs/xfs/scrub/quotacheck.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=9036e078bd51683e862afd5ed25ecba2f780b165

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

The original Linux kernel CVE announcement for CVE-2026-97544 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97544

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: 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).