* [CVE-2026-97433][MODERATE REGULAR] nvme: validate FDP configuration descriptor sizes [ Upstream
@ 2026-09-24 23:31 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-24 23:31 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-97433
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: nvme: validate FDP configuration descriptor sizes [ Upstream
Commit: 97efd7a41aac08b43ea2337c5913a2bc75484f9f
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=97efd7a41aac08b43ea2337c5913a2bc75484f9f
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97433
Analysis date: Thu, 24 Sep 2026 19:31:47 -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-2026-97433 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97433
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: MODERATE REGULAR
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-2026-97433 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-97433 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';CWE-125;*CWE-835;*CWE-20;BEST CVSS score: '4.6';DESCR 'A malformed FDP configuration log from an NVMe controller can contain a zero or oversized descriptor size. The host parser can then loop without progress or access data beyond the received log buffer while walking configuration descriptors. For the CVSS the PR:N because the triggering input is supplied by the NVMe controller and no local account on the affected host is required after a malicious or faulty device is connected. The attack vector is AV:P because reliable exploitation requires physical control of an NVMe device or an equivalent ability to provide a malicious virtual controller. Impact is denial of service through CPU exhaustion or a host kernel crash. The patch context does not demonstrate a write primitive, use after free, information disclosure path, or plausible privilege escalation.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) YES NVME LOG LINUS NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 1
* Conservative score: 1
* Raw paranoid score: 1
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate**::
The score reflects a controller supplied malformed log that can cause an unbounded parser loop or an invalid host kernel read. No score floor applies because there is no UAF, write primitive, authorization bypass, ownership violation, or demonstrated attacker controlled reuse.
2. Signal breakdown
* +1 Firmware mediated external influence. The FDP configuration log is supplied by the NVMe controller and descriptor size is parsed from controller controlled data.
* +1 Reliable kernel DoS. A zero descriptor size can prevent parser progress and an oversized descriptor can cause parsing beyond the received log buffer. The stated effects support CPU exhaustion or a kernel fault.
* -1 Corruption is highly constrained. The patch establishes only malformed size handling and an out of bounds read or loop. It does not establish an out of bounds write, active object corruption, or a user visible data disclosure path.
Important non-awarded signals:
* Controlled reclaim is not demonstrated.
* Arbitrary or directed kernel write is not demonstrated.
* RealUAF is not established.
* Confidentiality is not awarded because no bytes are shown to be copied back to userspace, network peers, or the controller.
* Integrity is not awarded because the parser does not write through the malformed descriptor.
* Remote network reachability is not established. The input is received from a local NVMe controller or equivalent virtual controller.
* Privilege escalation is not supported by the patch context.
* No extra Availability point is awarded because CPU exhaustion and a possible kernel fault are alternative consequences of the same parser defect.
3. Reachability analysis
The vulnerable parser consumes an FDP configuration log returned by an NVMe controller. A malicious or faulty physical NVMe device can supply a zero or oversized dsze field. An equivalent scenario may exist where an attacker can provide a malicious virtual NVMe controller, but the supplied patch does not establish a complete unprivileged virtual-device attack chain.
Host-admin-equivalent privilege is not required after an attacker can provide the malformed controller response. Therefore HostAdminRequired is NO. This does not mean that ordinary local users can attach or emulate an NVMe controller. No namespace scoped capability path is established, so NamespaceScopedPrivilege is UNKNOWN.
The relevant prerequisite is control of device firmware, physical device attachment, or a controller-emulation layer. No race is involved. The malformed FDP log is processed deterministically when the host queries FDP granularity.
4. Primitive and severity interpretation
The exact primitive is unchecked descriptor-size arithmetic while walking the controller supplied FDP configuration log. Before the fix, dsze equal to zero could leave the parser at the same descriptor, while an oversized dsze could advance the parser beyond the validated log boundary.
This is not a lifetime defect. No freed object is referenced, no refcount is mutated after object destruction, and no stale structured object is consumed. It is therefore not a Class A or Class B corruption issue. PrimitiveClass is CLASS_C because the demonstrated effect is invalid parser state leading to a loop, invalid read, warning, or host DoS.
The practical consequence is controller induced CPU consumption or a possible kernel crash. A stronger consequence such as information disclosure, memory corruption, host privilege escalation, or guest to host escape is speculative and unsupported by the supplied patch. ImportantCandidate is NO and AutoDowngradeAllowed is YES because the established primitive is constrained and crash or DoS oriented.
5. One-sentence report phrase
A malformed FDP configuration descriptor from an NVMe controller can use a zero or oversized dsze value to cause non progressing parser iteration or an out of bounds host kernel read, resulting in a possible denial of service.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
Confirm whether the target environment permits untrusted physical NVMe devices, hot plug storage, passthrough devices, or attacker controlled virtual NVMe controllers. If none apply, practical exposure is limited.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: nvme: validate FDP configuration descriptor sizes [ Upstream
Commit: 97efd7a41aac08b43ea2337c5913a2bc75484f9f
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=97efd7a41aac08b43ea2337c5913a2bc75484f9f
Changed files:
drivers/nvme/host/core.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=97efd7a41aac08b43ea2337c5913a2bc75484f9f
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-97433 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97433
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: Not available
The Best / paranoid CVSS vector: AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
The Best / paranoid CVSS score: 4.6
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: MODERATE
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): MODERATE REGULAR
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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