* [CVE-2026-90238][LOW] media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path [ Upstream
@ 2026-09-17 23:48 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-17 23:48 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-90238
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path [ Upstream
Commit: 74669cc3483e9729ca26b4e06a096ccdd607db64
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=74669cc3483e9729ca26b4e06a096ccdd607db64
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90238
Analysis date: Thu, 17 Sep 2026 19:48:21 -0400
ActionableScore: 1
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-2026-90238 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90238
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-2026-90238 LOW https://www.kernelcve.org/list/?q=CVE-2026-90238 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:N/I:N/A:H';*CWE-833;CWE-667;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'A self-deadlock occurs in isp4sd_pwron_and_init because the function already holds ops_mutex and its initialization error path calls isp4sd_pwroff_and_deinit which attempts to acquire the same non-recursive mutex again. Any failure while powering the ISP4 device, setting its performance state, starting the interface, or creating response threads can leave the calling thread blocked and the media device unavailable. For the CVSS the PR:L value is used because a local process normally needs permission to access and initialize the affected media device, while full administrative privileges are not necessarily required. AC:H reflects the additional requirement that a device initialization stage must fail. The issue is not network reachable. The demonstrated impact is denial of service against the ISP4 device, with possible wider availability impact if the blocked operation interferes with runtime PM, suspend, or shutdown. No UAF, OOB access, information leak, or write primitive is established by the affected path.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) SKIP CVE-2026-90238 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: url YES NO NO unknown MAYBE OOB DEADLOCK DANGER INIT ERRORPATH HARDWARE DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 - - checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 1
* Conservative score: 1
* Raw paranoid score: 1
* Paranoid score: 1
* No floor or cap was applied.
* Final recommended bucket: **Ordinary Moderate**::
2. Signal breakdown
* +1 Availability impact realistic. An initialization failure deterministically causes recursive acquisition of `ops_mutex`, blocking the calling thread and making the ISP4 device unavailable.
* +0 Reliable kernel crash or strong host DoS. The supplied evidence establishes a device-path deadlock, not a kernel panic or host-wide fatal failure.
* +0 Memory corruption. No UAF, OOB access, stale object, arbitrary write, refcount corruption, or ownership violation is established.
* +0 Runtime-PM underflow and unpowered MMIO. These are hazards of unconditional teardown, but the vulnerable path first blocks while reacquiring `ops_mutex`. The evidence does not establish that these operations execute or produce an independent security primitive.
* +0 Remote reachability. No network-controlled path is present.
* +0 Local unprivileged trigger. Callers and device-node permissions do not positively establish that an ordinary user can cause both initialization and the required failure.
* No privilege penalty was applied because host-admin-equivalent privilege is not positively established.
* No hardware rarity penalty was applied. The path is hardware-specific, but the supplied evidence does not establish that AMD ISP4 hardware is sufficiently rare to justify a reduction.
* No timing penalty was applied. This is a deterministic recursive-lock sequence after an initialization error, not a race.
* No additional paranoid point was awarded for possible suspend or shutdown interference because that consequence is not demonstrated and would describe the same availability failure.
3. Reachability analysis
The affected system must contain and use the AMD ISP4 media driver. The vulnerable sequence occurs when `isp4sd_pwron_and_init()` is entered and a power, performance-state, interface-start, or response-thread initialization stage fails.
The supplied context does not show the callers or establish whether an ordinary user with access to a V4L2 device, a compositor or camera service, or only a privileged driver-management path can initiate the complete sequence. Therefore `HostAdminRequired=UNKNOWN`. No namespace-scoped capability or namespace-mediated trigger is involved, so `NamespaceScopedPrivilege=NO`.
The physical ISP4 device and loaded driver are prerequisites, but no separate attacker-controlled privileged setup is demonstrated. There is no network trigger. There is also no race to win. Once an initialization failure reaches the old error path, the self-deadlock follows deterministically.
4. Primitive and severity interpretation
The exact primitive is recursive acquisition of a non-recursive mutex by the same thread. `isp4sd_pwron_and_init()` already holds `ops_mutex`, then calls `isp4sd_pwroff_and_deinit()`, which attempts to acquire that mutex again.
This is neither fixed stale storage nor an active structured-object UAF. No object lifetime ends, no dangling reference survives, and no second release or refcount mutation occurs. The bug is therefore `CLASS_C`, representing deterministic invalid synchronization and device-level denial of service without an independently useful corruption primitive.
The demonstrated consequence is a blocked initialization thread and loss of ISP4 device availability. Wider interference with runtime PM, suspend, or shutdown is conceivable but not established. The potential runtime-PM underflow and unpowered MMIO operations are avoided by the staged unwind, but they do not justify corruption scoring because the old path deadlocks before completing the nested teardown.
`ImportantCandidate=NO` because there is no memory corruption, authorization bypass, ownership violation, host-wide crash, or exploitation leverage beyond the deadlock. `AutoDowngradeAllowed=YES` because no unresolved security primitive would be lost by treating this as an ordinary device-local availability issue.
5. One-sentence report phrase
An AMD ISP4 initialization failure can recursively acquire `ops_mutex` and deadlock the calling thread, leaving the media device unavailable without establishing memory corruption or a network-reachable attack path.
6. Manual review recommendation
NO MANUAL CHECK NEEDED
The patch establishes a deterministic device-path self-deadlock with no UAF, corruption, security-boundary bypass, or demonstrated host-wide failure.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path [ Upstream
Commit: 74669cc3483e9729ca26b4e06a096ccdd607db64
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=74669cc3483e9729ca26b4e06a096ccdd607db64
Changed files:
drivers/media/platform/amd/isp4/isp4_subdev.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=74669cc3483e9729ca26b4e06a096ccdd607db64
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-90238 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-90238
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:L/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:N/I:N/A:H
The Best / paranoid CVSS score: 4.7
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: unknown
Paranoid ActionableScore: 1
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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