* [CVE-2026-80782][MODERATE 7.0] HID: magicmouse: do not keep a stale msc->input if no input is claimed [ Upstream
@ 2026-09-04 16:04 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-04 16:04 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-80782
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: HID: magicmouse: do not keep a stale msc->input if no input is claimed [ Upstream
Commit: c3597923932bb90d4fc2186aef552f6677175e4a
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c3597923932bb90d4fc2186aef552f6677175e4a
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80782
Analysis date: Fri, 04 Sep 2026 12:04:46 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES
Summary:
A stale msc input pointer in HID magicmouse can survive hidinput_connect failure and be dereferenced by later input reports, causing a kernel crash and requiring manual review due to the UAF lifetime primitive.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-80782 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80782
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-2026-80782 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-80782 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H';*CWE-416;*CWE-672;CWE-703;Other CVSS 'AV:A/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:H';BEST CVSS score: '7.1';DESCR 'A use-after-free can occur in the HID magicmouse driver because magicmouse_input_mapping caches an input_dev pointer in msc input before the HID input claim is guaranteed to succeed. If hidinput_connect later fails and frees the created input_dev objects, magicmouse_probe can still continue when other listeners such as raw_event, hidraw, or hiddev are present, leaving msc input as a dangling pointer. A later input report can pass the existing NULL checks and dereference freed memory, causing at least a kernel crash and potentially broader memory corruption impact. For the CVSS the PR:N is used because the paranoid scenario assumes an external malicious or malfunctioning HID device and does not require a local account on the victim. The issue is not reachable over IP networking. Practical exploitation requires Bluetooth adjacent proximity or USB physical access, user action to connect or pair the device, and the hidinput failure path such as input_register_device error. Impact is at least denial of service and worst case may include confidentiality or integrity impact due to the UAF primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5) YES USB RACE ERRORPATH UAF HARDWARE LINUS KPANIC KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFDH NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=5
ActionableScoreLower=4
## 1. ActionableScore
* Conservative score: 4
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**
## 2. Signal breakdown
* Firmware-mediated external influence: +1. Trigger depends on an external HID device path, such as Bluetooth-adjacent or USB-attached Magic Mouse or Magic Trackpad behavior.
* Generic memory corruption: +2. The patch describes a real stale pointer to a freed input_dev, i.e. a UAF candidate, not just a NULL dereference.
* Real lifetime corruption: +1. hidinput_connect failure frees input_dev objects while msc->input may still reference one of them.
* Reliable kernel crash / strong DoS: +1. A later input report can pass NULL checks and dereference freed memory.
* Hard or unreliable trigger condition: -1. Exploitation requires the hidinput_connect or input_register_device failure path and a later input report, so the trigger is not a simple always-on data path.
* Paranoid weak LPE concern: +1. The UAF is in a kernel object reachable from later event/raw_event processing, but no controlled reclaim, callback control, or write primitive is demonstrated.
Conservative total: 1 + 2 + 1 + 1 - 1 = 4
Paranoid total: 4 + 1 = 5
## 3. Reachability analysis
The bug can be triggered by a malicious, malformed, or malfunctioning HID device if it can cause or coincide with the hidinput error path and then deliver later input reports. No local Linux user account is required in the external-device scenario, but practical triggering requires Bluetooth proximity with pairing/user interaction or USB physical access. It is not reachable over IP networking.
Namespaces and containers do not materially lower the requirement because the relevant path is device attachment and HID driver probing, not a namespaced syscall API. The affected code is in a device-specific HID driver, so exposure is narrower than a core HID or input subsystem bug, but the lifetime failure is real.
Call-site confidence: high. The commit message explicitly describes the cached pointer, the hidinput_disconnect free path, the missing HID_CLAIMED_INPUT claim, and later raw_event/event dereference behavior.
## 4. Severity interpretation
This is stronger than an ordinary Moderate cleanup because it is a real stale pointer / UAF condition in kernel HID input handling. Realistic impact is most likely local/adjacent denial of service via kernel crash. Important-class handling is not fully justified from the patch alone because there is no demonstrated attacker-controlled reclaim, arbitrary write, type confusion, or callback hijack primitive. However, because the bug class is UAF and the freed object can be dereferenced later, it should not be auto-closed without manual review.
## 5. One-sentence report phrase
A stale msc input pointer in HID magicmouse can survive hidinput_connect failure and be dereferenced by later input reports, causing a kernel crash and requiring manual review due to the UAF lifetime primitive.
## 6. Manual review recommendation
MANUAL CHECK REQUIRED
Reason: this is a real UAF/stale-pointer lifetime bug with adjacent or physical external-device influence. The demonstrated impact is DoS, but the memory-lifetime primitive is security-relevant enough to require manual triage.
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: HID: magicmouse: do not keep a stale msc->input if no input is claimed [ Upstream
Commit: c3597923932bb90d4fc2186aef552f6677175e4a
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c3597923932bb90d4fc2186aef552f6677175e4a
Changed files:
drivers/hid/hid-magicmouse.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=c3597923932bb90d4fc2186aef552f6677175e4a
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-80782 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80782
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:A/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:H
The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
The Best / paranoid CVSS score: 7.1
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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