[CVE-2026-72496][LOW] RDMA/bnxt_re: Proper rollback if the ioremap fails [ Upstream

[CVE-2026-72496][LOW] RDMA/bnxt_re: Proper rollback if the ioremap fails [ Upstream

[AL-KERNEL]

CVE: CVE-2026-72496
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: RDMA/bnxt_re: Proper rollback if the ioremap fails [ Upstream
Commit: 303f6fef95df5e5316970746d861cf6daeeca77f
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=303f6fef95df5e5316970746d861cf6daeeca77f
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72496
Analysis date: Sun, 16 Aug 2026 01:19:34 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like. NO MANUAL CHECK REQUIRED COULD BE AUTOCLOSED
Manual review required: YES

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-72496 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72496

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: YES

A detailed explanation of the methodology and priority rules is included
at the end of this message.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-72496	LOW	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:N/A:H';CWE-252;CWE-703;*CWE-772;**CWE-476;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'bnxt_qplib_alloc_dpi could report success after ioremap or ioremap_wc failed, leaving a DPI entry allocated with a NULL doorbell mapping. This creates an inconsistent RDMA driver state and may break later operations that expect dpi dbr to be valid. For the CVSS the PR:L is used in the paranoid score because a local user with access to RDMA uverbs or a service using the RDMA device may be able to request DPI allocation without full administrator privileges. The issue is not directly network reachable and depends on local access to the bnxt_re RDMA device plus an ioremap failure condition. Impact is primarily denial of service or resource exhaustion, not a proven information leak or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like. NO MANUAL CHECK REQUIRED COULD BE AUTOCLOSED (with actual score 2)	YES	LOCK NOMEMCHK SIMPLEFIX NETWORK MEMORY  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	YES	NO	checked

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

ActionableScore=2
ActionableScoreLower=1

1. ActionableScore
* Conservative score: 1
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like. NO MANUAL CHECK REQUIRED COULD BE AUTOCLOSED**::

2. Signal breakdown
* Local unprivileged trigger: +1 in the paranoid interpretation, because RDMA uverbs access may be available to a local user or service account with device permissions, not necessarily full root.
* Availability impact realistic: +1, because a successful allocation with a NULL doorbell mapping can plausibly break later RDMA operations, leak a DPI slot, or cause driver failure.
* Rollback/error-path concern: +1 only in the paranoid interpretation, because the function claimed a DPI table bit and app_tbl entry but did not roll them back on ioremap failure.
* Hard or special trigger condition: -1, because exploitation depends on ioremap or ioremap_wc failure, which is not normally attacker-controlled or reliably triggerable.
* No generic memory corruption: +0, because the patch shows missing NULL handling and rollback, not UAF, double free, OOB write, type confusion, refcount takeover, or controlled overwrite.
* No privilege escalation signal: +0, because there is no supported path to attacker-controlled memory reuse, arbitrary write, callback control, or sensitive object corruption.

3. Reachability analysis
The likely trigger is local access to the bnxt_re RDMA device path that can request DPI allocation. In typical deployments this is restricted to RDMA-capable hosts and users or services with device access, but it does not necessarily require full host root. Namespaces or containers could matter only if RDMA device access is delegated into the container. The affected path is hardware and driver specific, and the failure also requires an ioremap failure, so realistic exploitation conditions are narrow. This is not directly network reachable.

4. Severity interpretation
This behaves more like ordinary Moderate or Low-like driver error-handling fallout than an Important-class vulnerability. The theoretical concern is a NULL doorbell mapping and inconsistent DPI table state after a failed ioremap. The realistic evidence supports local DoS or resource leak only. There is no demonstrated memory corruption primitive, no confidentiality impact, no integrity impact, and no practical privilege escalation evidence.

5. One-sentence report phrase
bnxt_qplib_alloc_dpi could return success after ioremap failure, leaving an allocated DPI slot with a NULL doorbell mapping and potentially causing local RDMA driver malfunction or denial of service under low-memory or mapping-failure conditions.

6. Manual review recommendation
NO MANUAL CHECK NEEDED. This can be autocLOSED for urgent triage because it is a local driver rollback bug with constrained reachability, special failure preconditions, and no supported memory corruption or privilege escalation primitive. Call-site confidence: medium.

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

Patch: RDMA/bnxt_re: Proper rollback if the ioremap fails [ Upstream
Commit: 303f6fef95df5e5316970746d861cf6daeeca77f
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=303f6fef95df5e5316970746d861cf6daeeca77f

Changed files:
  drivers/infiniband/hw/bnxt_re/qplib_res.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=303f6fef95df5e5316970746d861cf6daeeca77f

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

The original Linux kernel CVE announcement for CVE-2026-72496 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72496

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: 1
  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 alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).