* [CVE-2026-98908][LOW] net: microchip: sparx5: clean up PSFP resources on flower setup failure [ Upstream
@ 2026-10-26 20:57 21% AL-KERNEL
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From: AL-KERNEL @ 2026-10-26 20:57 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-98908
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: net: microchip: sparx5: clean up PSFP resources on flower setup failure [ Upstream
Commit: a7625d408f7f0535c2b0f05d53231d6496acd48b
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a7625d408f7f0535c2b0f05d53231d6496acd48b
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98908
Analysis date: Mon, 26 Oct 2026 16:57:46 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO
Summary:
Sparx5 PSFP flower setup failures can leak stream and flow-meter resources, including a reused meter reference, causing constrained offload-resource depletion without shown memory corruption.
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ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98908 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98908
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-2026-98908 LOW https://www.kernelcve.org/list/?q=CVE-2026-98908 CHECK WITH IMPACT FROM ORIG NN IMPORTANT | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=LOW RESULT=DIFF TEMP_DISTANCE_MERGE_SKIP=AEGIS_NO_POSITIVE_SEVERITY_EVIDENCE (final Legacy and Aegis differ; FINAL: LOW, Aegis: MODERATE_KPANIC) Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';*CWE-772;CWE-404;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '2.5';DESCR 'This is a cleanup logic bug and persistent PSFP resource leak in the Sparx5 tc flower offload path. Stream gate, flow meter, and stream filter resources could remain allocated when a later VCAP action setup step failed. Reuse of an existing flow meter also incremented its reference count while leaving psfp_fmid as zero, so failure cleanup could target flow meter zero instead of releasing the acquired reference. For the CVSS the PR:H value reflects that reliable triggering normally requires CAP_NET_ADMIN and control of tc flower configuration for a Sparx5 device. The issue is local and hardware specific. The demonstrated primitive is resource retention rather than memory corruption, and impact is limited to reduced availability of PSFP offload resources unless repeatable host wide exhaustion is established. Automated impact decision path. The original SimpleNet classifier selected IMPORTANT. The primary LLM estimated paranoid CVSS 2.5 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage IMPORTANT to MODERATE_KPANIC because the CVSS score, vector or bug class threshold rule was applied. ActionableScore thresholds stage MODERATE_KPANIC to LOW because the ActionableScore threshold rule was applied. final reconciliation stage LOW to LOW because KP specialist did not establish a qualifying panic and the cross model evidence reconciliation rule was applied. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS and DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 and DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 and KPANIC_UNSUPPORTED_REMOVED and V64_AEGIS_UNSUPPORTED_PROMOTION_BLOCKED. The independent weaker Aegis shadow evaluated CVSS 2.5 and ActionableScore 1 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The models disagreed but the aggregation rules retained the production result. The final reported impact is LOW.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) MAYBE REMOTE SIMPLEFIX ERRORPATH NETWORK LINUS LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 KPANIC_UNSUPPORTED_REMOVED V64_AEGIS_UNSUPPORTED_PROMOTION_BLOCKED - - checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
RequiresHostUID0=NO
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO
1. ActionableScore
* Raw base score: 1.
* Conservative score: 1; no floor or cap applied.
* Raw paranoid score: 1.
* Paranoid score: 1; no technically supported stronger primitive.
* Final recommended bucket: **Ordinary Moderate**::
2. Signal breakdown
* +1 Concrete persistent kernel resource/reference leak: setup acquires stream-gate, flow-meter, and stream-filter resources but previously returned directly after later failures without releasing them. Reusing a flow meter also increments its pool reference while failing to return its actual ID, preventing correct release.
* No crash/strong DoS point: exhaustion of PSFP offload resources is plausible, but host-wide exhaustion, panic, or persistent system unavailability is not shown.
* No privilege penalty: CAP_NET_ADMIN is indicated, but whether the complete trigger necessarily requires host-admin-equivalent authority over a host-owned Sparx5 device is not conclusively established.
* No UAF, double release, OOB write, shared-backing write, authorization bypass, controlled corruption, or confidentiality/integrity effect is shown.
* B5-R does not apply: there is no retry-accumulated heap OOB write or later consumption of corrupted structured state.
* No race penalty: this is an ordered setup-failure unwind defect, not evidence of a narrow timing race.
3. Reachability analysis
The path is tc flower PSFP hardware-offload configuration on a Sparx5 device and ordinarily involves CAP_NET_ADMIN plus control of that device. Numeric host UID 0 is not inherently required. The evidence does not establish whether a delegated/net-namespace capability can perform the complete hardware-offload and failure sequence, so both effective host-admin and namespace scope remain unknown. Specialized Sparx5 hardware and a later setup failure are prerequisites, but rarity is insufficiently established for a score penalty.
4. Primitive and severity reading
The proven primitive is persistent leakage of allocated PSFP resources and a reused flow-meter reference. The stale `psfp_fmid` can also make cleanup target ID 0, but the supplied evidence does not show deletion of an active victim resource or memory corruption. This is CLASS_C resource-management/availability behavior, not a lifetime-after-free primitive. Important-grade leverage and a trust-boundary effect are absent; automatic downgrade is therefore allowed.
5. One-sentence report phrase
Sparx5 PSFP flower setup failures can leak stream and flow-meter resources, including a reused meter reference, causing constrained offload-resource depletion without shown memory corruption.
6. Manual review advice
NO MANUAL CHECK NEEDED
The patch demonstrates a bounded hardware-resource cleanup defect without an unresolved corruption or authorization primitive.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: net: microchip: sparx5: clean up PSFP resources on flower setup failure [ Upstream
Commit: a7625d408f7f0535c2b0f05d53231d6496acd48b
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a7625d408f7f0535c2b0f05d53231d6496acd48b
Changed files:
drivers/net/ethernet/microchip/sparx5/sparx5_psfp.c
drivers/net/ethernet/microchip/sparx5/sparx5_tc_flower.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=a7625d408f7f0535c2b0f05d53231d6496acd48b
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98908 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98908
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:L/UI:N/S:U/C:N/I:N/A:L
The Best / paranoid CVSS score: 2.5
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 [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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