* [CVE-2026-98155][MODERATE REGULAR] accel/qaic: Address potential out-of-bounds read in resp_worker() [ Upstream
@ 2026-09-26 17:59 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-26 17:59 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-98155
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: accel/qaic: Address potential out-of-bounds read in resp_worker() [ Upstream
Commit: f4b64488f3deca63f7fbc7d7c3835b2e668003f9
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f4b64488f3deca63f7fbc7d7c3835b2e668003f9
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98155
Analysis date: Sat, 26 Sep 2026 13:59:35 -0400
ActionableScore: 0
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO
Summary:
A malformed response from a QAIC accelerator can make `resp_worker()` read beyond a slab allocation or loop indefinitely, potentially crashing the host kernel, but no disclosure, write primitive, or privilege escalation path is established.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98155 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98155
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-2026-98155 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-98155 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:L/UI:N/S:U/C:L/I:N/A:H';CWE-125;*CWE-20;*CWE-835;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.3';DESCR 'An out-of-bounds read in the QAIC accelerator control path can occur because resp_worker() manually parses an orphaned device response without the message length and transaction bounds checks used by decode_message(). A malformed wire message from the QAIC device can move the transaction header beyond the slab allocation and may cause an infinite loop or kernel panic. For the CVSS the PR:L value is used for the paranoid score because a delegated accelerator user or isolated service may be able to influence management transactions, although reliable triggering normally requires a faulty or compromised device or device firmware. The issue is not directly network reachable and requires access to a system with the QAIC device and driver active. Impact is at least denial of service through a kernel panic. A limited confidentiality impact is possible if the out-of-bounds read reaches adjacent slab data, but no reliable disclosure channel or memory write primitive is established.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0) SKIP CVE-2026-98155 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: url YES NO NO unknown MAYBE OOB DANGER HARDWARE MEMORY PACKET DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH - - checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=0
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
## 1. ActionableScore
* Raw conservative score: 0
* Conservative score: 0
* Raw paranoid score: 0
* Paranoid score: 0
* No floor or cap was applied.
* Final recommended bucket: **Ordinary Moderate**::
## 2. Signal breakdown
Positive signals:
* +1 Firmware-mediated external influence. The malformed message originates from the QAIC device, so hostile influence requires device or firmware mediation rather than direct network access.
* +1 Reliable kernel crash or strong DoS. The commit explicitly identifies infinite loops and kernel panics as realistic consequences.
Negative signals:
* -2 Rare hardware-only prerequisite. The vulnerable path requires a system equipped with the specialized QAIC accelerator. The malformed input must come from that physical device or its firmware.
Not awarded:
* No corruption bonus. The established primitive is an OOB read, not an OOB write or lifetime violation.
* No confidentiality point. Adjacent slab memory may be read internally, but no path returning those bytes to userspace, the device, or a network peer is established.
* No integrity point. There is no write, object replacement, refcount mutation, or active-state corruption.
* No remote-reachability point. Device or firmware mediation is material.
* No local-unprivileged point. A local user might influence DBC lifetime, but the evidence does not show that such a user can generate the required malformed device response.
* No extra Availability point. The infinite-loop or panic consequence is already represented by the single DoS point.
* No UAF, controlled reclaim, arbitrary write, callback influence, or privilege-escalation point.
## 3. Reachability analysis
The complete trigger requires an active QAIC device, an orphaned deactivation response handled by `resp_worker()`, and a malformed wire message supplied by the device. A faulty or compromised device firmware can satisfy the malformed-message condition.
The supplied evidence does not establish that an ordinary local user, delegated accelerator process, or host administrator can deliberately make the device emit such a malformed response. Accordingly, host-admin requirements remain unknown rather than being assumed high or low.
No namespace-scoped capability path is shown. Prior installation and initialization of specialized QAIC hardware is required. The issue is not directly network-triggerable, and no timing race is involved.
## 4. Primitive and severity interpretation
The exact primitive is an unbounded transaction walk that can calculate `trans_hdr` beyond the received message slab allocation and then read fields from outside that allocation. This is a limited device-controlled OOB read with possible nontermination or kernel fault.
It is not a UAF, stale-object operation, repeated release, write primitive, or active structured-object replacement. The demonstrated consequences are host DoS through an infinite loop or kernel panic. A disclosure is theoretically conceivable only if the out-of-bounds bytes subsequently reach an observable output, but no such path is established here.
`PrimitiveClass=CLASS_C` is appropriate because the demonstrated behavior is invalid-read and crash behavior without an independently useful corruption primitive. `ImportantCandidate=NO` follows from the absence of disclosure, write, ownership violation, or meaningful privilege-escalation leverage. `AutoDowngradeAllowed=YES` because no unresolved Class A or Class B primitive would be discarded.
## 5. One-sentence report phrase
A malformed response from a QAIC accelerator can make `resp_worker()` read beyond a slab allocation or loop indefinitely, potentially crashing the host kernel, but no disclosure, write primitive, or privilege escalation path is established.
## 6. Manual review recommendation
MANUAL CHECK RECOMMENDED
Confirm whether an unprivileged or delegated QAIC user can induce malformed firmware responses and whether any decoder path can expose data read beyond the message buffer. Current evidence supports DoS only.
## 7. Call-site confidence
Call-site confidence: high
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: accel/qaic: Address potential out-of-bounds read in resp_worker() [ Upstream
Commit: f4b64488f3deca63f7fbc7d7c3835b2e668003f9
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f4b64488f3deca63f7fbc7d7c3835b2e668003f9
Changed files:
drivers/accel/qaic/qaic_control.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=f4b64488f3deca63f7fbc7d7c3835b2e668003f9
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-98155 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98155
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:H
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: 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: 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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