[CVE-2026-98497][MODERATE 7.0] net/mlx5e: fix swapped IPv6 IPsec policy masks

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-98497
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: net/mlx5e: fix swapped IPv6 IPsec policy masks
Commit: 3803dc8477f08e0dac4050cafee0de43f32727be
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3803dc8477f08e0dac4050cafee0de43f32727be
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98497
Analysis date: Sat, 24 Oct 2026 05:34:51 -0400
ActionableScore: 5
ActionableScore lower bound: unknown
Actionable bucket: Actionable Moderate / Strong Important candidate requiring manual review
Manual review required: YES

Summary:
Swapped IPv6 source and destination masks cause mlx5 IPsec hardware to consume active policies with transposed semantics, producing confirmed over- and under-matching with unresolved security-boundary consequences.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-98497 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98497

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
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CVE-2026-98497	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98497 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=MODERATE_KPANIC RESULT=SAME (final reconciliation agrees; DECISION: both MODERATE_KPANIC)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L';CWE-693;CWE-284;*CWE-20;Other CVSS 'AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L';BEST CVSS score: '7.7';DESCR 'IPv6 IPsec hardware policies in mlx5e can use different source and destination prefix lengths, but setup_fte_addr6 installed each generated mask in the opposite address field. The resulting hardware rule may miss packets covered by the intended policy and may match attacker controlled packets outside that policy, creating a potential IPsec enforcement and isolation failure rather than memory corruption. For the CVSS the PR:N value is used because an attacker who can send matching IPv6 traffic does not need an authenticated local user context, although an administrator must first configure mlx5 IPsec offload with unequal prefixes. Exploitation also depends on the affected mlx5 hardware path and on downstream XFRM behavior, so the base impact is limited while the paranoid score covers a plausible serious confidentiality or integrity boundary failure. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 7.7 and the production ActionableScore returned 5 with recommendation Actionable Moderate / Strong Important candidate requiring manual review. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage MODERATE_KPANIC to IMPORTANT because the CVSS score, vector or bug class threshold rule was applied. KP and FD specialist checks stage IMPORTANT to MODERATE_KPANIC because FD false positive review allowed a downgrade. The legacy KP specialist produced a review artifact and its decision was processed by the applicable KP rules. The legacy FD or DH downgrade specialist produced a review artifact and its decision was processed by the applicable downgrade and preservation rules. Exact triggered rule markers were INCREASED_TO_HIGH_BASED_ON_GUESSCVSS and DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFDH. The independent weaker Aegis shadow evaluated CVSS 0.0 and ActionableScore 1 with primitive class NONE and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is MODERATE_KPANIC.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate / Strong Important candidate requiring manual review (with actual score 5)	MAYBE	REMOTE OOB SIMPLEFIX NETWORK HARDWARE IPV6 KPANIC MEMORY  KPANIC INCREASED_TO_HIGH_BASED_ON_GUESSCVSS DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFDH	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=5
PrimitiveClass=CLASS_B
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=YES
ManualReview=REQUIRED
AutoDowngradeAllowed=NO
RequiresHostUID0=NO
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=UNRESOLVED
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw base score: 5.
* Conservative score: 5; no floor or cap applied.
* Raw paranoid score: 5.
* Paranoid score: 5; downstream confidentiality, plaintext bypass, or protected-resource access is not proven.
* Final recommended bucket: **Actionable Moderate / Strong Important candidate requiring manual review**::

2. Signal breakdown

* +2 — Strong semantic policy reinterpretation: the source and destination IPv6 masks are installed in opposite active hardware match fields. Attacker-influenced packet addresses are consequently evaluated using the wrong policy semantics.
* +1 — Hardware-mediated external influence: network traffic reaches the affected mlx5 IPsec hardware rule after administrative policy setup.
* +1 — Integrity impact plausible: the patch confirms both under-matching of policy-covered traffic and over-matching of traffic outside the policy.
* +1 — Concrete processing chain: unequal prefixes → swapped masks → hardware rule consumption → incorrect packet classification.
* No memory corruption, UAF, arbitrary write, disclosure, LPE, or kernel crash is shown.
* No extra authorization-bypass score: the evidence does not establish a concrete DENY-to-ALLOW access-control decision or show whether software XFRM processing compensates.
* No confidentiality bonus: cleartext transmission, key exposure, or protected traffic disclosure is unproven.
* NEW52/B5-R and NEW53/B3-PENDING do not apply.

3. Reachability analysis

A host administrator must first configure mlx5 IPv6 IPsec offload with unequal source and destination prefixes. Once that state exists, an external sender can influence packet source/destination addresses evaluated by the malformed hardware rule without host-administrator credentials. Thus the exercising attacker is below host admin, although prior privileged setup and affected mlx5 hardware are prerequisites.

The supplied evidence does not establish a namespace-based complete setup path, so namespace-scoped privilege remains unknown. No race is involved.

4. Primitive and severity reading

The primitive is active security-policy state with source/destination semantics transposed and subsequently consumed by privileged NIC/XFRM packet processing. This is CLASS_B semantic policy corruption, not kernel memory corruption.

Proven effects are incorrect hardware matches and misses. Whether this permits plaintext bypass, unauthorized network access, isolation failure, or only incorrect offload/fallback behavior is unresolved. The specific IPsec trust boundary and active downstream consumer justify Important-candidate review, but not a confirmed Important impact claim.

AuthorizationDecisionBypass is NO because no concrete mandatory guard changes from DENY to ALLOW in the supplied call path. Consequently B4-PENDING is not confirmed.

Auto-downgrade is disallowed because automatically treating the defect as ordinary packet misclassification would discard the unresolved IPsec enforcement-boundary impact.

5. One-sentence report phrase

Swapped IPv6 source and destination masks cause mlx5 IPsec hardware to consume active policies with transposed semantics, producing confirmed over- and under-matching with unresolved security-boundary consequences.

6. Manual review advice

MANUAL CHECK REQUIRED

Determine whether missed rules fall back safely to software XFRM processing and whether over-matched traffic can cross an IPsec or tenant isolation boundary.

7. Call-site confidence

Call-site confidence: medium

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UPSTREAM PATCH SUMMARY
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Patch: net/mlx5e: fix swapped IPv6 IPsec policy masks
Commit: 3803dc8477f08e0dac4050cafee0de43f32727be
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3803dc8477f08e0dac4050cafee0de43f32727be

Commit description:

IPv6 XFRM policies may use different source and destination prefix
lengths. mlx5e_ipsec_policy_mask() builds the corresponding masks
independently, but setup_fte_addr6() installs each mask in the opposite
address field.

When the prefix lengths differ, this makes the source match use the
destination prefix and the destination match use the source prefix. The
resulting hardware rule can both miss traffic covered by the policy and
match traffic outside it.

Install each mask in its corresponding match field.

Fixes: ca7992f ("net/mlx5e: Properly match IPsec subnet addresses")
Cc: stable@vger.kernel.org
Signed-off-by: Andrea Parri <parri.andrea@gmail.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20260917115542.177675-1-parri.andrea@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec_fs.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=3803dc8477f08e0dac4050cafee0de43f32727be

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

The original Linux kernel CVE announcement for CVE-2026-98497 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98497

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:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
  The Best / paranoid CVSS vector: AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
  The Best / paranoid CVSS score: 7.7

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: 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).