[CVE-2026-98365][MODERATE 7.0] RDMA/rxe: Fix integer overflow in mr_check_range() leading to OOB access [ Upstream

[CVE-2026-98365][MODERATE 7.0] RDMA/rxe: Fix integer overflow in mr_check_range() leading to OOB access [ Upstream

[AL-KERNEL]

CVE: CVE-2026-98365
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: RDMA/rxe: Fix integer overflow in mr_check_range() leading to OOB access [ Upstream
Commit: b7d2118660545a00b21e83010ded1a231c6fb8c5
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b7d2118660545a00b21e83010ded1a231c6fb8c5
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98365
Analysis date: Thu, 08 Oct 2026 07:12:04 -0400
ActionableScore: 5
ActionableScore lower bound: unknown
Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review
Manual review required: YES

Summary:
No one-sentence report phrase was found.

======================================================================
ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-98365 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98365

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-2026-98365	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98365 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=4 LEGACY=MODERATE_KPANIC RESULT=SAME (legacy and Aegis reconciliation agree; DECISION: both MODERATE_KPANIC)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H';CWE-190;CWE-125;*CWE-787;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '8.8';DESCR 'An integer overflow in the RXE RDMA memory region range check can allow a crafted RETH IOVA and length to bypass MR bounds validation. A remote RoCE peer may cause rxe_mr_iova_to_index and rxe_mr_copy_xarray to use a very large index, resulting in out of bounds kernel memory access and potentially a kernel crash or memory corruption. For the CVSS the PR:N applies because the attack is performed by a remote RDMA peer and does not require local code execution on the target. AV:A is used because RXE RoCE is normally reachable only from an RDMA fabric or local network segment, not directly from the public Internet. The base impact includes limited confidentiality and integrity risk with high availability impact. The paranoid score uses high confidentiality integrity and availability impact because the patch context indicates an out of bounds read write primitive that warrants manual exploitation review.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 5)	MAYBE	OOB NETWORK LINUS  KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFDH	-	-	checked

======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================

ActionableScore=5
PrimitiveClass=CLASS_A
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=YES
ManualReview=REQUIRED
AutoDowngradeAllowed=NO

1. ActionableScore

* Raw conservative score: 5
* Conservative score: 5
* Raw paranoid score: 5
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**::

2. Signal breakdown

* +2 Directly network-triggerable RDMA access. The supplied analysis establishes that an unauthenticated remote RoCE peer can send a crafted RDMA Read or Write RETH reaching `mr_check_range()`.
* +2 Strong kernel corruption primitive. The integer wraparound bypasses MR bounds validation and leads to `mr->page_info[huge]` access in the RXE data path. The supplied context explicitly identifies OOB read and write behavior.
* +1 Reliable kernel crash or strong DoS. The invalid index is reported to cause a kernel Oops.

Important non-awarded signals:

* Controlled reclaim is not demonstrated.
* Arbitrary or attacker-directed kernel write is not demonstrated. The attacker controls IOVA, length, and potentially RDMA Write payload, but the ultimate kernel memory target after the invalid `page_info` lookup is not established by the supplied code.
* Confidentiality is not separately awarded. The patch establishes an OOB read possibility, but no read-back or network-visible disclosure path is shown.
* Integrity is not separately awarded. OOB write is a strong corruption primitive, but modification of a specific protected kernel object, credential, or other principal data is not demonstrated.
* No local-unprivileged-trigger point is awarded because the established attacker model is remote RDMA peer access, not local syscall reachability.
* No subsystem rarity penalty is applied. RXE is optional and requires an RDMA deployment, but optional deployment alone is not evidence that the attacker cannot reach the exposed responder.
* No host-admin penalty is applied. The supplied context positively establishes remote unauthenticated peer triggering, so host administrator privileges are not required for the attacker.

3. Reachability analysis

The evaluated attacker is an unauthenticated remote peer with access to the target RXE RoCE fabric or network segment. The supplied context establishes that a crafted RDMA Read or Write RETH can reach the vulnerable MR range validation without local execution on the target.

RXE must be enabled and an RDMA responder application must expose a queue pair and memory region to the peer. These are deployment prerequisites, but they are not attacker privilege requirements once the service is reachable. RDMA access normally requires connectivity to the relevant RoCE fabric or local Layer 2 storage network, which supports AV:A rather than public-Internet AV:N.

HostAdminRequired is NO because the complete described trigger is performed remotely by the peer. NamespaceScopedPrivilege is UNKNOWN because no namespace-specific RXE, RDMA CM, queue pair, or memory registration setup is shown. No race or special hardware timing is involved.

4. Primitive and severity interpretation

The exact bug is an integer overflow in the MR range validation expression:

`iova + length > mr->ibmr.iova + mr->ibmr.length`

A crafted large IOVA can wrap the addition and cause `mr_check_range()` to accept an invalid range. Subsequent RXE code derives a huge page index and accesses `mr->page_info[huge]` outside the intended memory-region metadata array.

This is not a UAF, cleanup-only stale access, or a warning-only defect. It is an attacker-controlled bounds-check bypass leading to an OOB kernel memory access on a remote RDMA data path. The supplied evidence explicitly identifies both read and write operation contexts, so the primitive is classified as CLASS_A.

The demonstrated practical consequence is kernel Oops or denial of service. A stronger confidentiality, integrity, or privilege-escalation consequence is plausible because the affected path handles RDMA memory transfers, but it is not independently demonstrated: the patch does not show controlled target selection, arbitrary kernel read-back, controlled object replacement, credential corruption, or a completed LPE chain.

ImportantCandidate is YES because a remotely reachable OOB write-capable kernel memory primitive needs exploitation review even though arbitrary kernel read/write is not proven. AutoDowngradeAllowed is NO because automatically treating this only as a crash would discard the established attacker-controlled OOB access primitive.

5. One-sentence report phrase

An unauthenticated RoCE peer can exploit an integer overflow in RXE MR range validation to bypass bounds checks and trigger out of bounds kernel memory access through a crafted RDMA RETH, causing at least a remote kernel DoS and requiring manual review for memory corruption impact.

6. Manual review recommendation

MANUAL CHECK REQUIRED

The supplied context establishes remote attacker reachability and an OOB read/write primitive in kernel RDMA memory handling. Manual review should inspect `rxe_mr_iova_to_index()` and `rxe_mr_copy_xarray()` to determine whether the invalid `page_info` access can produce attacker-controlled page selection, data disclosure, or a directed write beyond the demonstrated crash.

7. Call-site confidence

Call-site confidence: medium

======================================================================
UPSTREAM PATCH SUMMARY
======================================================================

Patch: RDMA/rxe: Fix integer overflow in mr_check_range() leading to OOB access [ Upstream
Commit: b7d2118660545a00b21e83010ded1a231c6fb8c5
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b7d2118660545a00b21e83010ded1a231c6fb8c5

Changed files:
  drivers/infiniband/sw/rxe/rxe_mr.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=b7d2118660545a00b21e83010ded1a231c6fb8c5

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-98365 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98365

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:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS vector: AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 8.8

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: 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 alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).