* [CVE-2026-92480][MODERATE REGULAR] scsi: ufs: core: Validate string descriptors [ Upstream
@ 2026-09-18 8:01 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-18 8:01 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-92480
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: scsi: ufs: core: Validate string descriptors [ Upstream
Commit: 66da25277256b6bf4c3fdbf3c9bfd43324c9cf25
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=66da25277256b6bf4c3fdbf3c9bfd43324c9cf25
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92480
Analysis date: Fri, 18 Sep 2026 04:01:24 -0400
ActionableScore: 3
ActionableScore lower bound: 2
Actionable bucket: Borderline / manual review recommended
Manual review required: YES
Summary:
No one-sentence report phrase was found.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-92480 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92480
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-2026-92480 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-92480 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:L/UI:N/S:U/C:L/I:N/A:H';CWE-125;*CWE-20;CWE-131;Other CVSS 'AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L';BEST CVSS score: '5.3';DESCR 'A malformed UFS string descriptor can cause an out of bounds read in ufshcd_read_string_desc because the UTF-16 payload length is handled as bytes while utf16s_to_utf8s expects a count of UTF-16 code units. The raw descriptor path can also copy bLength bytes from a pointer that already skips the descriptor header, which can read beyond the response buffer. For the CVSS the PR:L is used in the paranoid local scenario because reliable triggering generally requires a local process or service that can cause descriptor reads on a system with a malformed or attacker controlled UFS device. The issue is not network reachable. Impact is at least limited confidentiality exposure from kernel memory overread and possible denial of service if the invalid read faults or triggers hardening checks.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 3) YES DISK ERRORPATH HARDWARE INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 YES NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=3
ActionableScoreLower=2
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 2
* Conservative score: 2
* Raw paranoid score: 3
* Paranoid score: 3
* Final recommended bucket: **Borderline / manual review recommended**::
No floor or cap changed the score.
2. Signal breakdown
Conservative signals:
* +1 Firmware-mediated external influence: the malformed string descriptor is supplied by UFS device or firmware data, not by ordinary direct network traffic.
* +1 Read-only OOB / layout defect: the patch establishes that descriptor length, payload offset, copy size, conversion count, and allocation size were inconsistent and could cause reads beyond the descriptor buffer.
Paranoid additional signal:
* +1 Confidentiality plausible: the overread data can be copied or converted into an output buffer returned to callers, including the raw descriptor path used for the RPMB device-ID ABI, so limited kernel-memory disclosure is plausible enough for manual review.
Non-awarded signals:
* +0 Real UAF: no stale lifetime object, double release, refcount misuse, or post-free access is established.
* +0 Controlled corruption: no OOB write, arbitrary write, object replacement, controlled reclaim, or callback influence is shown.
* +0 Reliable kernel crash: invalid read could fault or trigger hardening in some conditions, but the patch does not establish a reliable host-wide crash path.
* +0 Remote reachability: this is device or firmware mediated and not directly network reachable.
* +0 Integrity impact: no unauthorized modification of kernel or user data is established.
* +0 Strong LPE leverage: no privilege escalation primitive is demonstrated.
* +0 Concrete repeated release/refcount: not applicable. There is no first release that can end lifetime, no surviving exact dangling reference, and no second lifetime mutation.
* +0 Floor 5: not applicable because RealUAF=NO.
3. Reachability analysis
The malformed data comes from UFS string descriptors, so the realistic attacker is a malicious, compromised, or defective UFS device or firmware path. A local process may be able to cause descriptor reads indirectly through normal device probing or management paths, but the security-relevant malformed payload is not ordinary user-controlled input.
Host administrator privilege is not required by the malformed device itself, so HostAdminRequired=NO. This is not namespace scoped, and no network namespace or delegated capability path is relevant. There is no direct network attack surface. Prior host setup is limited to having a UFS device and the affected driver path active, which is common on systems using UFS storage, but attacker control of the descriptor normally requires device or firmware influence. No race condition is involved.
4. Primitive and severity interpretation
The exact primitive is a read-only out-of-bounds access in `ufshcd_read_string_desc()`. In the ASCII path, the UTF-16 payload byte count was passed where a UTF-16 code-unit count was expected. In the raw path, `kmemdup()` copied `bLength` bytes starting after the descriptor header, which could read beyond the response buffer.
This is not an active structured UAF and not fixed stale storage after free. It is a bounded descriptor-buffer overread with possible limited disclosure through returned string buffers. The demonstrated consequence is memory overread. The speculative consequence is a fault or hardening-triggered crash, but that is not strong enough to score as reliable DoS. PrimitiveClass=CLASS_C because the issue is an invalid read / OOB read without an independently useful corruption primitive.
ImportantCandidate=NO because there is no Class A primitive, no RealUAF, no controlled corruption, no authorization bypass, and no demonstrated LPE. AutoDowngradeAllowed=YES because the unresolved risk is limited to a device-mediated OOB read with possible limited disclosure, not a strong corruption or boundary-bypass primitive. Operational severity is low-to-borderline Moderate, but manual review is useful because the copied overread bytes may reach externally visible consumers.
5. One-sentence report phrase
A malformed UFS string descriptor can cause `ufshcd_read_string_desc()` to read beyond the descriptor buffer during UTF-16 conversion or raw descriptor copying, creating a device-mediated limited information disclosure risk and possible fault without evidence of write corruption or privilege escalation.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
Manual review is recommended because this is a concrete OOB read from device-supplied data and the returned buffer may expose limited adjacent kernel memory, even though no UAF, write corruption, direct network trigger, or LPE primitive is established.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: scsi: ufs: core: Validate string descriptors [ Upstream
Commit: 66da25277256b6bf4c3fdbf3c9bfd43324c9cf25
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=66da25277256b6bf4c3fdbf3c9bfd43324c9cf25
Changed files:
drivers/ufs/core/ufshcd.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=66da25277256b6bf4c3fdbf3c9bfd43324c9cf25
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-92480 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92480
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:L/I:N/A:L
The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H
The Best / paranoid CVSS score: 5.3
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: 2
Paranoid ActionableScore: 3
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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