* [CVE-2026-92477][MODERATE REGULAR] scsi: ufs: debugfs: Reserve space for a string terminator [ Upstream
@ 2026-09-18 4:29 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-18 4:29 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-92477
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: scsi: ufs: debugfs: Reserve space for a string terminator [ Upstream
Commit: b43890843e834300f967c69e74c7c2eb22cb1664
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b43890843e834300f967c69e74c7c2eb22cb1664
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92477
Analysis date: Fri, 18 Sep 2026 00:29:03 -0400
ActionableScore: 2
ActionableScore lower bound: 1
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-2026-92477 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92477
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-2026-92477 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-92477 CHECK WITH IMPACT FROM ORIG NN MODERATE 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-170;CWE-125;*CWE-20;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.3';DESCR 'ufs_saved_err_write copies user supplied debugfs input into a 16 byte zero initialized stack buffer and then passes it to kstrtoint. An input of exactly 16 bytes can fill the whole buffer and remove the only trailing NUL terminator, so kstrtoint may read past the end of val_str while looking for the end of the string. For the CVSS the PR:L is used in the paranoid score because some systems may expose debugfs access through delegated administration, container root, or a local service even though normal direct access is usually administrator only. The issue is not network reachable and requires local access to the UFS debugfs control path. Impact is mainly denial of service through a warning, failed parsing, or possible kernel crash on hardened or debug builds. Confidentiality is limited at most because this is an out of bounds read from kernel stack memory without a direct copy back to userspace. Integrity and privilege escalation are not strongly supported because the patch shows missing string termination rather than an overwrite primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) YES WRITE OOB DISK SIMPLEFIX DEBUGFS DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH YES NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=2
ActionableScoreLower=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 1
* Conservative score: 1. No floor or cap applied.
* Raw paranoid score: 2
* Paranoid score: 2. No floor or cap applied.
* Final recommended bucket: **Ordinary Moderate**::
2. Signal breakdown
Conservative positive signals:
* +1 Weak or indirect corruption candidate. The patch establishes a missing string terminator that can make `kstrtoint()` read past the end of a 16 byte stack buffer.
Conservative negative signals:
* No negative privilege penalty applied. Direct write permission to the specific debugfs file is not visible in the supplied patch, so host admin is likely but not positively established from the provided context.
Paranoid additional signals:
* +1 Paranoid limited fault or DoS concern. A kernel stack out of bounds read in a debugfs write handler could theoretically cause a failed parse, warning, or crash on some hardened or debug configurations, but the evidence does not support a reliable host-wide crash.
Important non-awarded signals:
* RealUAF not awarded. No object lifetime violation, stale reference, double free, or repeated refcount mutation is shown.
* Strong corruption not awarded. The bug is an out of bounds read caused by missing NUL termination, not an out of bounds write.
* Controlled reclaim not demonstrated.
* Arbitrary write not demonstrated.
* Confidentiality not awarded. The out of bounds bytes are read internally by `kstrtoint()` and no copy back to userspace or other disclosure path is shown.
* Integrity not awarded. The patch does not establish unauthorized modification of protected kernel state.
* Reliable kernel crash not awarded conservatively. The commit does not show an observed panic or a deterministic fault.
* Remote reachability not established. This is a local debugfs control path.
* Extra availability not awarded because there is no distinct persistent unavailability mechanism.
* ImportantCandidate not set because the primitive is limited to an internal stack OOB read without disclosure, write, UAF, authorization bypass, or demonstrated LPE.
3. Reachability analysis
The vulnerable path is `ufs_saved_err_write()` in UFS debugfs. Triggering requires writing to a UFS debugfs attribute that is intended for error handling or fault triggering. Debugfs interfaces are normally administrator oriented and often require root or equivalent permissions, but the supplied diff does not show the exact file mode or complete access checks.
HostAdminRequired is therefore UNKNOWN rather than YES. It is plausible that practical triggering requires host administrator access, but that is not proven by the provided patch fragment. NamespaceScopedPrivilege is UNKNOWN because no evidence shows that the complete operation is available through attacker-created namespaces or namespace-scoped capabilities.
There is no network path. There is no race. No special rare hardware penalty is applied beyond noting that the vulnerable interface exists only on systems with UFS debugfs support and relevant UFS driver exposure.
4. Primitive and severity interpretation
The exact primitive is a missing string terminator for a stack buffer. `val_str[16]` is zero initialized, but the old check allowed `count == sizeof(val_str)`. A 16 byte write fills the whole buffer and removes the only trailing NUL, after which `kstrtoint()` may continue reading adjacent stack bytes while parsing.
This is a read-only stack out of bounds access. It is not an active structured object UAF, not fixed stale storage, and not a cleanup or destructor lifetime issue. There is no concrete repeated release or refcount operation. The demonstrated consequence is malformed parsing or possible local DoS under unfavorable conditions. The speculative consequence is limited internal stack overread, but no practical leak or privilege escalation path is established.
PrimitiveClass is CLASS_C because the behavior is primarily invalid read or crash oriented without an independently useful corruption primitive. ImportantCandidate is NO because there is no meaningful unresolved Important-grade primitive. AutoDowngradeAllowed is YES because the issue can be treated as ordinary Moderate or Low-like triage unless product-specific evidence shows that this debugfs node is exposed to less privileged users or that the parser result reaches a stronger security effect.
5. One-sentence report phrase
A missing NUL terminator in the UFS debugfs `ufs_saved_err_write()` path can make `kstrtoint()` read past a small stack buffer when a local writer supplies exactly 16 bytes, but no disclosure, write primitive, UAF, or network trigger is established.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
A brief manual check is useful to confirm the debugfs file permissions and whether malformed parsed values can affect UFS error handling in a stronger way, but the supplied evidence supports only a limited local OOB read with ordinary Moderate or Low-like practical risk.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: scsi: ufs: debugfs: Reserve space for a string terminator [ Upstream
Commit: b43890843e834300f967c69e74c7c2eb22cb1664
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b43890843e834300f967c69e74c7c2eb22cb1664
Changed files:
drivers/ufs/core/ufs-debugfs.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=b43890843e834300f967c69e74c7c2eb22cb1664
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-92477 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92477
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:L/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: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: 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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