* [CVE-2026-90329][MODERATE 7.0] HID: synchronize input before cleaning up a failed probe [ Upstream
@ 2026-09-17 22:55 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-17 22:55 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-90329
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: HID: synchronize input before cleaning up a failed probe [ Upstream
Commit: 3ffb088a2ed34ca982cfc2c81d107ce370aa45f1
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3ffb088a2ed34ca982cfc2c81d107ce370aa45f1
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90329
Analysis date: Thu, 17 Sep 2026 18:55:18 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review
Manual review required: YES
Summary:
A race in HID failed-probe cleanup can allow an in-flight report callback to access a freed hidraw object and take its list lock, causing a kernel UAF crash and requiring manual review for possible stronger memory-corruption impact.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90329 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90329
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 7.0
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-2026-90329 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-90329 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:H/I:H/A:H';*CWE-416;CWE-362;CWE-667;Other CVSS 'AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A race in the HID failed probe path can allow report callbacks to run while __hid_device_probe() is freeing driver resources and clearing the device driver pointer. A report can enter hidraw_report_event() while the related hidraw object is being released, which creates a use after free when the callback touches the freed object lock or list state. For the CVSS the PR:L is used for the paranoid case because a low privileged local user may be able to reach this path if the environment exposes virtual HID creation or delegated device control such as UHID. The issue is not directly network reachable in the normal USB HID case. Bluetooth or other HID transports may change practical exposure, but they still depend on local pairing and device access conditions. Impact is at least denial of service via kernel crash. Because the bug is a race based use after free in kernel memory, worst case confidentiality and integrity impact should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 5) YES DANGER USB UAF LINUS SYZBOT KPANIC NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=5
ActionableScoreLower=4
PrimitiveClass=CLASS_B
RealUAF=YES
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=YES
ManualReview=REQUIRED
AutoDowngradeAllowed=NO
## 1. ActionableScore
* Raw conservative score: 3
* Conservative score: 4
* Raw paranoid score: 5
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**::
Conservative floor applied: Real UAF floor 4 changed 3 -> 4 because a concrete post-lifetime object use is established and host-admin-equivalent privilege is not positively required.
No paranoid floor or cap was applied.
## 2. Signal breakdown
Conservative signals:
* +2 Real UAF / active lifetime violation. The commit directly states that a report callback may enter `hidraw_report_event()` while failed-probe cleanup frees the associated hidraw object.
* +1 Reliable kernel crash / strong DoS. The stale callback takes the freed object's list lock, which is a realistic kernel UAF crash path.
* +1 Firmware/device-mediated external influence. The attacker-controlled input is HID report delivery, normally mediated through a HID device or HID transport.
* -1 Hard or narrow timing. The conservative path requires overlap between failed probe cleanup and an in-flight report callback.
Paranoid additional interpretation:
* +1 Structured stale-object exploitation leverage. The stale path is not only a passive read. It enters HID report processing and touches lock/list state in a freed hidraw object, so post-free structured processing remains unresolved.
* Race penalty withheld in paranoid score because a malicious or virtual HID source may repeatedly drive report delivery during probe/failure attempts.
Important non-awarded signals:
* Controlled reclaim not demonstrated.
* Arbitrary write not demonstrated.
* Direct network reachability not established.
* Concrete repeated release/refcount mutation not established.
* Strong LPE leverage +2 not awarded.
* Extra Availability +1 not awarded because it would double-count the same crash.
* C/I bonuses not awarded as direct consequences. They remain unresolved review concerns rather than established impacts.
Repeated release/refcount checklist:
* First release can end lifetime: not the scored mechanism.
* Exact same reference survives to a second put/release: not established.
* Second operation is a real lifetime/refcount mutation: not established.
* Concrete repeated release/refcount +1 awarded: no.
* Paranoid repeated-refcount leverage +1 awarded: no.
* FLOOR 5 for repeated release applied: no.
## 3. Reachability analysis
The clearest trigger is a malicious or abnormal HID device or HID transport that can deliver reports while driver probe is in progress and then fails. This does not require host administrator privileges in the physical-device attacker model, but it does require device or transport reachability.
A local virtual HID path such as UHID may make the issue reachable by a local low-privileged user in some environments, but that depends on `/dev/uhid` permissions and local policy. The complete local unprivileged chain is not proven from the supplied patch alone.
This is not namespace-scoped. No evidence shows that an attacker-created namespace is sufficient for the complete trigger.
No direct TCP/IP network trigger is established. Bluetooth HID or similar transports may change practical exposure, but that depends on pairing and local device policy.
The race is tied to failed probe cleanup versus concurrent report callback execution. It is timing-dependent, but repeated connection or virtual-device attempts can make testing and triggering more practical.
## 4. Primitive and severity interpretation
The exact primitive is a race-based use-after-free of a hidraw object during failed HID probe cleanup. The freed object is an active structured kernel object, not merely a fixed DMA buffer or passive metadata.
The stale use occurs in a report callback, while cleanup frees resources and clears driver state. The stale callback may take the freed object's list lock, so the post-lifetime operation can modify synchronization/list-related state at a freed address.
This is CLASS_B: a real kernel lifetime/corruption primitive requiring exploitation-leverage analysis. It is not CLASS_A because controlled reclaim, attacker-shaped replacement contents, arbitrary read/write, callback control, or demonstrated privilege escalation are not established.
Demonstrated consequence is kernel crash / DoS. Speculative consequence is stronger memory corruption if the freed hidraw object is reclaimed and the stale lock/list operation affects a new object. That stronger consequence is technically plausible enough for manual review, but not proven enough for CLASS_A.
ImportantCandidate=YES because this is an active structured UAF in kernel memory with unresolved post-free lock/list behavior. AutoDowngradeAllowed=NO because automatic closure would discard a concrete unresolved UAF primitive beyond a simple validation bug.
Operationally this is at least Actionable Moderate. It is not a confirmed Important vulnerability without additional evidence of reliable local reachability, controlled reclaim, or privilege escalation.
## 5. One-sentence report phrase
A race in HID failed-probe cleanup can allow an in-flight report callback to access a freed hidraw object and take its list lock, causing a kernel UAF crash and requiring manual review for possible stronger memory-corruption impact.
## 6. Manual review recommendation
MANUAL CHECK REQUIRED
Reason: this is a concrete kernel UAF in active HID report processing, and the stale operation touches lock/list state after object lifetime ended. Controlled exploitation is not demonstrated, but the primitive should not be auto-downgraded as crash-only without review.
## 7. Call-site confidence
Call-site confidence: high
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: HID: synchronize input before cleaning up a failed probe [ Upstream
Commit: 3ffb088a2ed34ca982cfc2c81d107ce370aa45f1
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3ffb088a2ed34ca982cfc2c81d107ce370aa45f1
Changed files:
drivers/hid/hid-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=3ffb088a2ed34ca982cfc2c81d107ce370aa45f1
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90329 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90329
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:H/PR:N/UI:N/S:U/C:N/I:N/A:H
The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
The Best / paranoid CVSS score: 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: 4
Paranoid ActionableScore: 5
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: YES
Published priority for this report (same as in Subject): MODERATE 7.0
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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