* [CVE-2026-89952][MODERATE REGULAR] mtd: rawnand: validate ONFI extended parameter page sections
@ 2026-09-16 19:16 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-16 19:16 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-89952
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: mtd: rawnand: validate ONFI extended parameter page sections
Commit: 1bf148fabe6463422195b7cc43b3412533f1dc21
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1bf148fabe6463422195b7cc43b3412533f1dc21
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89952
Analysis date: Wed, 16 Sep 2026 15:16:47 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate
Manual review required: YES
Summary:
No one-sentence report phrase was found.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-89952 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89952
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: YES
A detailed explanation of the methodology and priority rules is included
at the end of this message.
======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================
CVE-2026-89952 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-89952 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:L/I:L/A:H';CWE-125;*CWE-20;CWE-130;Other CVSS 'AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.7';DESCR 'ONFI extended parameter page parsing in the raw NAND driver can read beyond the allocated buffer when a device reports a malformed page length or malformed section lengths. The parser treats the data as a fixed header followed by variable length sections, but the old code did not prove that the fixed header, the current section, and the ECC section fields fit inside the allocation. For the CVSS the PR:N is used because a crafted or malicious NAND device can provide malformed ONFI data during probe without a prior software privilege on the target. The issue is not network reachable. It requires physical or supply chain control over the NAND device or an equivalent platform level way to provide malformed ONFI parameter data. Impact is mainly denial of service through kernel fault or failed boot/probe. Because this is an out of bounds read from kernel memory during hardware discovery, limited confidentiality or integrity impact is kept only in the paranoid score and this case should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) MAYBE READ HARDWARE LINUS - - checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=2
ActionableScoreLower=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 1
* Conservative score: 1
* Raw paranoid score: 2
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate**::
No floor or cap was applied.
2. Signal breakdown
Conservative positive signals:
* +1 Weak invalid read / OOB read candidate. The parser may read beyond the kmalloc allocation when the ONFI extended parameter page length or section lengths are malformed.
* +1 Device supplied malformed input. The malformed data comes from NAND ONFI parameter data during device probe, so external hardware or supply chain influence is plausible.
Conservative negative signals:
* -1 Physical or supply chain constrained reachability. Practical triggering requires a malicious or faulty NAND device, physical replacement, supply chain control, or equivalent platform level control over ONFI data.
Paranoid additional signal:
* +1 Plausible strong DoS. A malformed page may cause a kernel fault, failed probe, or boot time device initialization failure, although a reliable host wide crash is not fully demonstrated.
Important non-awarded signals:
* RealUAF not awarded. No lifetime violation or stale post-free object use is shown.
* Controlled reclaim not demonstrated.
* Arbitrary write not demonstrated.
* OOB write not demonstrated.
* Confidentiality not awarded as an ActionableScore signal because no user visible or network visible disclosure path is established.
* Integrity not awarded because the primitive is read-side parsing of malformed data, not unauthorized modification.
* Remote reachability not established. This is not a packet-triggered or network service path.
* Extra availability not awarded beyond the paranoid DoS point.
* ImportantCandidate not awarded because the primitive is a constrained OOB read during hardware discovery without a demonstrated boundary bypass or exploitation primitive.
3. Reachability analysis
The realistic attacker is a physical, supply chain, or platform-level actor able to provide malformed ONFI extended parameter page data to the raw NAND driver. No host administrator privilege is needed after the malicious device data is presented to the kernel, so HostAdminRequired is NO.
This is not namespace scoped. User namespaces, network namespaces, and container capabilities do not provide the relevant access path. NamespaceScopedPrivilege is NO.
There is no direct network reachability. The vulnerable operation occurs during NAND detection and ONFI extended parameter parsing. Prior host setup may include having a system that uses raw NAND and probes ONFI data, but the attacker-relevant prerequisite is control over the device supplied parameter page rather than a local software privilege.
No race is involved. No special timing penalty is applied.
4. Primitive and severity interpretation
The exact primitive is a read beyond the allocated ONFI extended parameter page buffer while walking a fixed header and variable length sections. The patch adds checks that the full fixed header fits, that each section fits in the remaining page area, and that the ECC section is large enough before reading fields from struct onfi_ext_ecc_info.
This is fixed hardware supplied storage parsed during probe, not an active structured UAF. There is no cleanup/destructor stale reference, no repeated release/refcount mutation, and no evidence of attacker-controlled replacement of kernel objects.
PrimitiveClass is CLASS_C because the demonstrated behavior is invalid read / malformed parser state with likely DoS or probe failure consequences, not an independently useful corruption primitive.
Demonstrated consequence: malformed device data can cause out-of-bounds read behavior and device/probe failure risk.
Speculative consequence: limited C/I impact was used in the supplied paranoid CVSS hint, but the ActionableScore rules do not count C/I without a disclosure path, write primitive, or security-sensitive value influence.
ImportantCandidate is NO because the bug is constrained to physical/device supplied malformed data and lacks UAF, write corruption, authorization bypass, or a demonstrated exploit chain.
AutoDowngradeAllowed is YES because the issue is a constrained CLASS_C OOB read / DoS candidate without meaningful unresolved exploitation leverage.
Likely operational severity: Low-like to ordinary Moderate, with manual review recommended mainly because it is a kernel parser memory-safety bug in hardware-provided data.
5. One-sentence report phrase
Malformed ONFI extended parameter page data can make the raw NAND parser read beyond its allocated buffer during device probe, mainly risking a kernel fault or failed device initialization when a malicious or faulty NAND device is present.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
Reason: memory-safety parsing bug exists, but the primitive is a constrained OOB read from physical/device supplied data with no demonstrated disclosure, write corruption, UAF, or privilege escalation path.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: mtd: rawnand: validate ONFI extended parameter page sections
Commit: 1bf148fabe6463422195b7cc43b3412533f1dc21
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1bf148fabe6463422195b7cc43b3412533f1dc21
Commit description:
nand_flash_detect_ext_param_page() allocates the length declared by the
ONFI parameter page, then treats the data as a fixed header followed by
variable-length sections. It reads that header and advances over sections
without first proving that the fixed page and each current section fit in
the allocation.
Reject pages shorter than the fixed header, track the remaining variable
area while walking sections, and require the ECC section to contain every
field read from struct onfi_ext_ecc_info. Use device-scoped diagnostics
that identify the malformed ONFI section.
Fixes: 6dcbe0c ("mtd: get the ECC info from the Extended Parameter Page")
Cc: [email protected]
Signed-off-by: Pengpeng Hou <[email protected]>
Signed-off-by: Miquel Raynal <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Changed files:
drivers/mtd/nand/raw/nand_onfi.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=1bf148fabe6463422195b7cc43b3412533f1dc21
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-89952 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89952
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:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
The Best / paranoid CVSS vector: AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
The Best / paranoid CVSS score: 5.7
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: 1
Paranoid ActionableScore: 2
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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