[CVE-2026-72130][MODERATE 7.0] nvmet-auth: reject short AUTH_RECEIVE buffers [ Upstream

[CVE-2026-72130][MODERATE 7.0] nvmet-auth: reject short AUTH_RECEIVE buffers [ Upstream

[AL-KERNEL]

CVE: CVE-2026-72130
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: nvmet-auth: reject short AUTH_RECEIVE buffers [ Upstream
Commit: 80bf7b7f676e3987bbe06af3c359bd56ac91a5a9
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=80bf7b7f676e3987bbe06af3c359bd56ac91a5a9
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72130
Analysis date: Sun, 16 Aug 2026 06:49:34 -0400
ActionableScore: 8
ActionableScore lower bound: 6
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
A remote NVMe-oF initiator with access to an auth-enabled target can trigger a short AUTH_RECEIVE allocation that leads to a 16-byte kernel heap out-of-bounds write in the DH-HMAC-CHAP SUCCESS1 or FAILURE1 response builders.

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

The original Linux kernel CVE announcement for CVE-2026-72130 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72130

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.

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

CVE-2026-72130	MODERATE	CHECK WITH IMPACT FROM ORIG NN IMPORTANT	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-787;CWE-122;*CWE-20;Other CVSS 'AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '8.8';DESCR 'A heap out of bounds write in the NVMe-oF target authentication path occurs because AUTH_RECEIVE allocation length can be shorter than the fixed DH-HMAC-CHAP SUCCESS1 or FAILURE1 response written by nvmet_auth_success1() or nvmet_auth_failure1(). A remote initiator with access to an auth enabled target can trigger a 16 byte overwrite by supplying a very small AUTH_RECEIVE allocation length while the target is in the affected authentication state. For the CVSS the PR:N is used because successful authentication is not required, only reachability to the auth enabled NVMe-oF target and the ability to send the authentication command sequence. The issue is network reachable over the storage fabric, but NVMe-oF targets are typically deployed inside isolated storage or data center networks rather than the public Internet. Impact is at least denial of service via kernel memory corruption and in the paranoid interpretation may include confidentiality or integrity impact because the primitive is a controlled heap out of bounds write.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 8)	YES	WRITE OOB NVME LINUS KPANIC  DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFKP	YES	NO	checked

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

ActionableScore=8
ActionableScoreLower=6

## 1. ActionableScore

* Conservative score: 6
* Paranoid score: 8
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Remote reachable / network-triggerable: +2. A remote NVMe-oF initiator can send AUTH_RECEIVE to an auth-enabled target.
* Constrained kernel buffer overwrite: +1. The overwrite is a 16-byte heap OOB write, but the payload appears largely protocol or kernel-derived rather than an arbitrary attacker-chosen write.
* Reliable kernel crash / strong DoS: +1. Heap OOB write in kernel target code is a realistic crash or memory corruption condition.
* Integrity impact plausible: +1. Kernel heap overwrite can corrupt adjacent heap state even if exploitation is constrained.
* Availability impact realistic: +1. The trigger is protocol-level and can plausibly crash the target kernel repeatedly while the service is exposed.
* Important filesystem/storage path: +1. NVMe-oF target authentication is part of a storage fabric control path.
* Rare/configuration-dependent exposure: -1. Reachable only when in-band DH-HMAC-CHAP authentication is configured.

Paranoid additional interpretation:

* Memory corruption, strong corruption primitive: +2 instead of constrained +1. The bug is an actual heap OOB write past a kmalloc allocation in kernel context.
* Weak LPE concern: +1. Privilege escalation is not demonstrated, but kernel heap corruption in a remotely reachable target path warrants manual review.
* Confidentiality impact plausible: +1. Not demonstrated, but heap corruption can in worst case affect adjacent objects.
* Integrity impact plausible: +1. Stronger in paranoid scoring because adjacent heap object corruption could affect kernel state.

Call-site confidence: high. The commit directly identifies nvmet_execute_auth_receive(), nvmet_auth_success1(), nvmet_auth_failure1(), the short kmalloc buffer, and the fixed-size builders that write past it.

## 3. Reachability analysis

The bug is reachable by a remote NVMe-oF initiator that can connect to an auth-enabled NVMe target and send an AUTH_RECEIVE command with a too-small allocation length. Successful authentication is not required for the dangerous condition, because the issue is in the authentication exchange itself.

Namespaces and local privilege boundaries are not central here. The attacker is remote relative to the target kernel, but exposure is usually limited to storage or data-center networks rather than the public Internet. The affected path is not universally default-enabled because it requires NVMe-oF target mode and in-band DH-HMAC-CHAP authentication.

## 4. Severity interpretation

This should not be treated as an ordinary Moderate issue. The realistic impact is at least remote denial of service against an exposed auth-enabled NVMe-oF target. The theoretical worst case is more serious because the primitive is a kernel heap out-of-bounds write, although the overwrite is small and appears constrained.

The conservative result is Actionable Moderate. The paranoid result is a Strong Important candidate because network-reachable kernel heap corruption in a storage target authentication path deserves manual review.

## 5. One-sentence report phrase

A remote NVMe-oF initiator with access to an auth-enabled target can trigger a short AUTH_RECEIVE allocation that leads to a 16-byte kernel heap out-of-bounds write in the DH-HMAC-CHAP SUCCESS1 or FAILURE1 response builders.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED.

This is network-reachable kernel memory corruption with a concrete heap OOB write primitive, even though exploitation beyond DoS is not demonstrated and deployment is limited to auth-enabled NVMe-oF targets.

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

Patch: nvmet-auth: reject short AUTH_RECEIVE buffers [ Upstream
Commit: 80bf7b7f676e3987bbe06af3c359bd56ac91a5a9
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=80bf7b7f676e3987bbe06af3c359bd56ac91a5a9

Changed files:
  drivers/nvme/target/fabrics-cmd-auth.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=80bf7b7f676e3987bbe06af3c359bd56ac91a5a9

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

The original Linux kernel CVE announcement for CVE-2026-72130 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72130

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:L/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: 6
  Paranoid ActionableScore: 8

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).