* [CVE-2026-93103][LOW] RDMA/hfi1: Preserve unit 0 on allocation failure [ Upstream
@ 2026-09-18 5:13 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-18 5:13 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-93103
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: RDMA/hfi1: Preserve unit 0 on allocation failure [ Upstream
Commit: 852637d3ee56aed8ea3ee8948eda21eca406c051
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=852637d3ee56aed8ea3ee8948eda21eca406c051
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93103
Analysis date: Fri, 18 Sep 2026 01:13:15 -0400
ActionableScore: 2
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-2026-93103 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93103
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-2026-93103 LOW https://www.kernelcve.org/list/?q=CVE-2026-93103 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:N/I:L/A:H';CWE-763;*CWE-664;CWE-703;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:L';BEST CVSS score: '5.3';DESCR 'The hfi1 driver could remove an unrelated RDMA device from unit 0 when xa_alloc_irq failed during device allocation before the new device was inserted into the unit table. The failing object still had a zero initialized unit field, and the generic cleanup path could treat that value as a valid table index. For the CVSS the PR:L is used only in the paranoid interpretation because some environments may delegate device bind unbind or fault injection style controls to a reduced capability root or service account. In the typical host configuration PR:H is more realistic because reliable triggering requires administrative control of driver probing or PCI device management plus an allocation failure. The issue is not network reachable and is not triggered by RDMA traffic. Impact is mainly denial of service or integrity loss of the local RDMA device registry because an unrelated device may disappear from the unit table.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) YES SIMPLEFIX NETWORK HARDWARE LINUS DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3 NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=2
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 2
* Conservative score: 2
* Raw paranoid score: 2
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate**::
No floor or cap changed the score.
2. Signal breakdown
* +1 Weak or indirect kernel state corruption candidate. The failing hfi1 allocation path can erase unit table index 0 even though the new device was not inserted there.
* +1 Limited availability or integrity impact. An unrelated RDMA device may disappear from the driver unit table, causing device level malfunction or local service disruption.
* 0 Real UAF not awarded. The patch does not establish a use after free, stale dereference, double free, or repeated release on the same dangling reference.
* 0 Strong corruption not awarded. No controlled reclaim, arbitrary write, attacker controlled overwrite, callback control, or refcount takeover is shown.
* 0 Remote reachability not awarded. The issue is in local PCI RDMA driver initialization and is not triggered by RDMA network traffic.
* 0 Reliable host wide crash not awarded. The supplied evidence supports wrong removal from a registration table, not a demonstrated kernel panic.
* 0 Concrete repeated release or refcount signal not awarded. The fix avoids the generic cleanup path, but the supplied diff does not show a first release that can free an object followed by a second lifetime mutation on the same dangling reference.
* 0 C or I security impact beyond local device registry integrity not awarded. There is no evidence of protected data disclosure, privilege escalation, or unauthorized modification of unrelated user data.
* No negative privilege penalty was applied because the complete attacker reachable trigger is not fully established. Reliable triggering likely involves privileged PCI driver probing or fault injection, but the supplied evidence is not enough to score a strict host admin requirement as the only possible model.
3. Reachability analysis
The vulnerable path is hfi1_alloc_devdata during PCI RDMA device allocation. A practical trigger appears to require causing xa_alloc_irq to fail during driver probe or reinitialization, which normally implies host controlled device management, fault injection, or unusual allocation failure conditions.
Ordinary local unprivileged reachability is not established. Namespace scoped reachability is not established. This is not a network packet processing path and is not reachable by remote RDMA traffic alone.
There is a real hardware and configuration dependency because the hfi1 driver is for Intel Omni Path or compatible RDMA hardware, but no separate hardware penalty was applied in the score because the low score already reflects weak attacker reachability and limited consequence.
Race repeatability is not relevant. This is an ordered error path, not a timing race.
4. Primitive and severity interpretation
The exact primitive is incorrect cleanup of a global driver unit table entry after an allocation failure. The newly allocated device has a zero initialized dd unit field, and the generic cleanup path assumes the device was already inserted into the unit table. As a result, cleanup can erase an unrelated existing device at index 0.
This is an invalid state and wrong object selection bug, not a demonstrated UAF. It is not an active structured stale object with reuse leverage. It is not fixed stale storage touched after free. It is not a concrete repeated release or refcount mutation.
The demonstrated consequence is local RDMA device registry corruption and possible device level denial of service. A stronger consequence such as privilege escalation, arbitrary kernel write, host wide crash, or disclosure is speculative and not supported by the supplied patch.
PrimitiveClass is CLASS_C because the behavior is primarily invalid state and local device DoS without an independently useful corruption primitive. ImportantCandidate is NO because there is no meaningful unresolved memory corruption or security boundary bypass. AutoDowngradeAllowed is YES because the issue is constrained, local, and lacks UAF, repeated lifetime mutation, controlled corruption, or network reachability.
5. One-sentence report phrase
The hfi1 allocation error path can remove an unrelated RDMA device from unit table index 0 when xa_alloc_irq fails before insertion, causing local device registry corruption and possible device level denial of service.
6. Manual review recommendation
NO MANUAL CHECK NEEDED
Reason: the patch shows a constrained local driver cleanup bug with no UAF, no repeated refcount mutation, no remote reachability, and no supported privilege escalation primitive.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: RDMA/hfi1: Preserve unit 0 on allocation failure [ Upstream
Commit: 852637d3ee56aed8ea3ee8948eda21eca406c051
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=852637d3ee56aed8ea3ee8948eda21eca406c051
Changed files:
drivers/infiniband/hw/hfi1/init.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=852637d3ee56aed8ea3ee8948eda21eca406c051
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-93103 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93103
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:L/A:L
The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/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: 2
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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