* [CVE-2026-97543][LOW] xfs: destroy seen inode bitmap when we fail to add a dirpath
@ 2026-09-26 19:16 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-26 19:16 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-97543
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: xfs: destroy seen inode bitmap when we fail to add a dirpath
Commit: 3b10ca4302ee2dda4233f70b2033883ee376fa6a
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3b10ca4302ee2dda4233f70b2033883ee376fa6a
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97543
Analysis date: Sat, 26 Sep 2026 15:16:56 -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-2026-97543 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97543
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-2026-97543 LOW https://www.kernelcve.org/list/?q=CVE-2026-97543 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 'An error path in XFS directory tree scrub and repair can leak the seen inode bitmap when creation of a directory path object fails after the bitmap has been initialized. Repeated failures during XFS online scrub or repair operations may accumulate allocated memory and eventually cause resource exhaustion. For the CVSS the PR:H is selected because these maintenance operations normally require administrative control over the target XFS filesystem. The issue is not network reachable. Impact is limited to denial of service through memory consumption. No memory corruption primitive, information disclosure, integrity impact, or privilege escalation path is indicated by the affected code.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0) YES DISK SIMPLEFIX LEAK LINUS 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: -1
* Conservative score: 0
* Raw paranoid score: -1
* Paranoid score: 0
* Final recommended bucket: **Ordinary Moderate**::
The raw score is normalized to zero because ActionableScore does not use negative values.
2. Signal breakdown
* +1 Concrete persistent kernel resource leak. The error paths allocate and initialize `path->seen_inodes`, then free `path` without destroying the bitmap. The added `xino_bitmap_destroy()` directly establishes a missing cleanup operation.
* -2 Host-admin-equivalent privilege requirement. XFS online scrub and online repair are filesystem maintenance operations requiring administrative control over the target filesystem. The supplied context does not establish an ordinary-user path to invoke the affected scrub or repair operations.
* No additional resource-exhaustion point. Repeated accumulation is theoretically possible, but the patch does not establish attacker-controlled repetition, host-wide exhaustion, cgroup isolation bypass, or an immediate system-wide failure.
* No UAF, double free, stale-object use, refcount mutation, OOB access, arbitrary write, disclosure, authorization bypass, or ownership violation is established.
* No remote-reachability point. The affected path is local XFS scrub and repair control-plane activity.
* No filesystem integrity point. The bitmap leak does not alter XFS metadata, file contents, ownership, COW state, or access-control decisions.
3. Reachability analysis
The affected functions are reached while performing XFS directory-tree scrub or repair operations. These are administrative filesystem-maintenance operations, not ordinary file read or write paths.
The complete trigger requires invoking XFS online scrub or repair functionality and reaching an error after the seen-inode bitmap has been initialized but before a directory path name is appended. This is not established as reachable by an ordinary local user.
No network namespace, user namespace, delegated capability, special device, boot option, or hardware prerequisite is relevant. Namespace-scoped privilege is therefore NO because the relevant authorization is filesystem administration rather than a namespace-local capability chain.
4. Primitive and severity interpretation
The exact defect is a memory/resource leak. `xino_bitmap_destroy()` was omitted before `kfree(path)` on two error paths, leaving allocations associated with the empty seen-inode bitmap unreleased.
This is not an active stale-object problem. There is no post-free dereference, no second release, no refcount decrement through freed storage, no replacement object, and no attacker-controlled memory-corruption primitive.
The demonstrated consequence is limited memory consumption if the affected error path is repeatedly reached. A host-wide denial of service is not demonstrated by the patch. Privilege escalation, confidentiality impact, integrity impact, metadata corruption, and cross-boundary impact are speculative and unsupported.
PrimitiveClass is NONE because the patch establishes only a missing resource cleanup. ImportantCandidate is NO and AutoDowngradeAllowed is YES because no unresolved corruption, ownership, authorization, or lifetime primitive remains.
5. One-sentence report phrase
An XFS online scrub and repair error path can leak a seen inode bitmap, causing limited resource consumption during repeated privileged maintenance failures.
6. Manual review recommendation
NO MANUAL CHECK NEEDED
The patch fixes a straightforward missing cleanup of an internal bitmap in privileged XFS scrub and repair error paths, with no demonstrated memory-corruption or security-boundary primitive.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: xfs: destroy seen inode bitmap when we fail to add a dirpath
Commit: 3b10ca4302ee2dda4233f70b2033883ee376fa6a
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3b10ca4302ee2dda4233f70b2033883ee376fa6a
Commit description:
LOLLM observes a memory leak in xchk_dirtree_create_path if we create
the directory path object but appending the name to the path fails.
When this happens, we don't tear down the (empty) seen inode bitmap.
This is a pretty trivial error, but let's not leave logic bombs.
Do the same for a similar bug in xrep_dirtree_create_adoption_path.
Cc: [email protected] # v6.10
Fixes: 928b721 ("xfs: teach online scrub to find directory tree structure problems")
Signed-off-by: Darrick J. Wong <[email protected]>
Assisted-by: LOLLM # finding obvious bugs
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Carlos Maiolino <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Changed files:
fs/xfs/scrub/dirtree.c
fs/xfs/scrub/dirtree_repair.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=3b10ca4302ee2dda4233f70b2033883ee376fa6a
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-97543 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97543
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 [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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