* [CVE-2026-90147][LOW] clk: devres: fix cleanup in devm_clk_get_optional_enabled_with_rate() [ Upstream
@ 2026-09-18 3:09 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-18 3:09 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-90147
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: clk: devres: fix cleanup in devm_clk_get_optional_enabled_with_rate() [ Upstream
Commit: 9a365f41fe0f227ef5a269e240233bd0bffc66c9
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9a365f41fe0f227ef5a269e240233bd0bffc66c9
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90147
Analysis date: Thu, 17 Sep 2026 23:09:26 -0400
ActionableScore: 0
ActionableScore lower bound: unknown
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-2026-90147 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90147
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: LOW
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-2026-90147 LOW https://www.kernelcve.org/list/?q=CVE-2026-90147 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:H/UI:N/S:U/C:N/I:N/A:H';CWE-404;CWE-665;CWE-703;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.1';DESCR 'devm_clk_get_optional_enabled_with_rate registered a devres cleanup action before the clock rate was successfully set and before the clock was prepared and enabled. If clk_set_rate failed, later cleanup could call clk_disable_unprepare on a clock that had never been enabled, causing an invalid cleanup sequence and possible warning or device level availability impact. For the CVSS the PR:H is used because reliable triggering normally requires administrative control over driver probe failure, device binding, or module lifecycle. The issue is not network reachable and does not expose a direct memory corruption primitive. Impact is mainly denial of service or device malfunction, not information disclosure or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0) YES SIMPLEFIX HARDWARE LINUS YES NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=0
PrimitiveClass=NONE
RealUAF=NO
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: -1
* Conservative score: 0
* Raw paranoid score: -1
* Paranoid score: 0
* Applied conservative floor/cap: minimum score clamp -1 -> 0
* Applied paranoid floor/cap: minimum score clamp -1 -> 0
* Final recommended bucket: **Ordinary Moderate**::
2. Signal breakdown
Positive signals:
* +1: Invalid cleanup sequence. The helper could register clk_disable_unprepare cleanup before the clock was actually prepared and enabled, so an error in clk_set_rate could later disable or unprepare a clock that was never enabled.
Negative signals:
* -2: Host-admin-equivalent reachability is the supported practical model. Reliable triggering appears tied to driver probe failure, device binding, module lifecycle, or equivalent host device-management control.
Important non-awarded signals:
* Real UAF not awarded. No freed object or stale post-lifetime dereference is established.
* Concrete repeated release/refcount not awarded. The issue is not a second put or refcount mutation through a potentially dangling object.
* Controlled reclaim not demonstrated.
* Arbitrary write not demonstrated.
* C/I not awarded. No information disclosure or integrity modification primitive is established.
* Reliable kernel crash not awarded. The patch supports invalid cleanup and possible device-level malfunction, but not a demonstrated host-wide panic.
* Extra availability not awarded because only a limited cleanup/device-state failure is supported.
* Remote reachability not established.
* Namespace-scoped privilege not established.
* ImportantCandidate not set because there is no memory corruption, authorization bypass, shared ownership violation, or unresolved lifetime primitive.
3. Reachability analysis
The vulnerable operation is an internal clock framework devres helper used by kernel drivers. A practical attacker would need to influence a driver probe or device-management path so that devm_clk_get_optional_enabled_with_rate() is called and clk_set_rate() fails after the cleanup action has been registered. The supplied evidence does not show an ordinary local-user interface, network interface, namespace-scoped capability path, or packet-triggered path.
Host-admin-equivalent control is the supported model because reliable triggering normally requires control over device binding, driver loading, module lifecycle, or hardware or firmware state sufficient to make the rate-setting step fail. There is no indication that an attacker can instantiate the required device object or force the relevant clock failure from an unprivileged namespace. No special network exposure is involved. No race or narrow timing condition is required.
4. Primitive and severity interpretation
The exact primitive is an invalid resource-management cleanup order. The cleanup action for disabling and unpreparing a clock was registered before the clock was successfully prepared and enabled. If clk_set_rate() failed, later devres cleanup could call clk_disable_unprepare() on a clock that was not enabled by this helper.
This is not an active structured UAF and not fixed stale storage. It is not cleanup of a dangling pointer. It is a device-resource state mismatch in an error path. There is no concrete repeated release or refcount operation. There is no evidence that the first lifetime operation can free an object and that the same exact reference later receives a second lifetime mutation.
PrimitiveClass=NONE because no meaningful corruption, lifetime, ownership, authorization, COW, or security-boundary primitive is established. The demonstrated consequence is possible warning, invalid clock state cleanup, probe failure side effects, or device-level availability impact. Stronger consequences such as privilege escalation, information disclosure, arbitrary write, or host-wide crash are speculative and not supported by the patch. AutoDowngradeAllowed=YES because no unresolved Important-grade primitive would be lost by treating this as low-priority.
5. One-sentence report phrase
devm_clk_get_optional_enabled_with_rate() could register clock cleanup before successful enablement, so a rate-setting failure could later run an invalid disable or unprepare cleanup path with only device-level availability impact supported.
6. Manual review recommendation
NO MANUAL CHECK NEEDED
Reason: this is a host-admin-reachable driver resource cleanup ordering bug with no UAF, no memory corruption, no authorization bypass, no network reachability, and no supported privilege-escalation path.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: clk: devres: fix cleanup in devm_clk_get_optional_enabled_with_rate() [ Upstream
Commit: 9a365f41fe0f227ef5a269e240233bd0bffc66c9
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9a365f41fe0f227ef5a269e240233bd0bffc66c9
Changed files:
drivers/clk/clk-devres.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=9a365f41fe0f227ef5a269e240233bd0bffc66c9
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90147 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90147
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:H/PR:H/UI:N/S:U/C:N/I:N/A:L
The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
The Best / paranoid CVSS score: 4.1
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: unknown
Paranoid ActionableScore: 0
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: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW
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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