[CVE-2026-98097][MODERATE REGULAR] tipc: Dont send random pad bytes in RESET/ACTIVATE messages [ Upstream

[CVE-2026-98097][MODERATE REGULAR] tipc: Dont send random pad bytes in RESET/ACTIVATE messages [ Upstream

[AL-KERNEL]

CVE: CVE-2026-98097
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: tipc: Dont send random pad bytes in RESET/ACTIVATE messages [ Upstream
Commit: 48033a89356b8ae21a94db70c79bb6fcc91a23c2
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=48033a89356b8ae21a94db70c79bb6fcc91a23c2
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98097
Analysis date: Fri, 25 Sep 2026 15:08:54 -0400
ActionableScore: 4
ActionableScore lower bound: unknown
Actionable bucket: Borderline / manual review recommended
Manual review required: YES

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-98097 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98097

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 REGULAR
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-2026-98097	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98097 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:N/A:N';*CWE-200;CWE-908;CWE-201;Other CVSS 'AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N';BEST CVSS score: '6.5';DESCR 'TIPC RESET and ACTIVATE messages contain a fixed length interface name field, but strcpy writes only the string and its terminating zero byte. The remaining bytes can retain stale data from the skb and are transmitted to a remote TIPC peer, creating a kernel memory information disclosure. For the CVSS the PR:N value is used because no local account or privileges on the target are required once the attacker can communicate as a TIPC peer. AV:A is used because practical exploitation requires access to the same TIPC domain or an adjacent cluster network rather than unrestricted Internet reachability. The base impact is C:L because each disclosure is small and there is no demonstrated arbitrary read primitive. The paranoid impact is C:H because repeated protocol messages may expose multiple stale kernel memory fragments and therefore requires manual review. No memory write, privilege escalation, or denial of service primitive is demonstrated.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline / manual review recommended (with actual score 4) 	MAYBE	SIMPLEFIX TIPC SKB LINUS  DECREASED_TO_MODERATE70_BASED_ON_ACTIONABLESCORELOWERTHAN5 DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP	-	-	checked

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

ActionableScore=4
PrimitiveClass=CLASS_B
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=REQUIRED
AutoDowngradeAllowed=NO

1. ActionableScore

* Raw conservative score: 4
* Conservative score: 4
* Raw paranoid score: 4
* Paranoid score: 4
* No floor or cap applied.
* Final recommended bucket: **Borderline / manual review recommended**::

2. Signal breakdown

* +2 Remote reachable: an adjacent TIPC peer receives attacker-relevant RESET or ACTIVATE messages containing residual skb bytes.
* +1 Confidentiality plausible: the patch directly establishes that bytes not overwritten by `strcpy()` are transmitted to the remote system.
* +1 Practical exploit chain strongly implied: TIPC link protocol activity produces a direct kernel-memory-to-network disclosure without requiring local execution on the target.
* No UAF, OOB write, arbitrary write, controlled reclaim, callback influence, privilege escalation, or availability impact is established.
* No additional paranoid point: repeated messages may accumulate leaked fragments, but the patch does not establish an arbitrary-read primitive, useful byte selection, or sensitive contents.
* No niche-subsystem penalty: TIPC deployment limits exposure, but specialization alone is insufficient for a negative point.
* No privilege penalty: the evaluated attacker is a remote TIPC peer, not a local administrator.
* No separate broad-networking bonus: TIPC is not a common TCP/IP packet-processing path.

3. Reachability analysis

The attacker must be able to participate in the same TIPC domain or otherwise communicate as an adjacent TIPC peer. The vulnerable system must already have TIPC and an appropriate bearer configured, normally by an administrator, but the remote peer does not need a local account or host-admin privilege to receive the leaked bytes once that deployment exists.

The path is not ordinary public-Internet exposure. It is primarily relevant to cluster, telecom, and internal data-center networks using TIPC. No namespace capability, special hardware, race, or timing window is required by the disclosed mechanism. Repeated link resets or activations may permit repeated observations, but attacker control over the exact leaked contents is not established.

4. Primitive and severity interpretation

The exact primitive is disclosure of residual kernel skb bytes from a fixed-length protocol field. `strcpy()` writes the interface name and terminating zero but leaves the rest of the transmitted `TIPC_MAX_IF_NAME` field unchanged. The subsequent fixed message size makes those remaining bytes visible to the peer.

This is not a UAF or write-side memory corruption. It is classified as CLASS_B because a concrete kernel information-disclosure primitive exists, but it is bounded and lacks arbitrary address selection. The demonstrated consequence is limited kernel-memory disclosure. A substantial accumulated disclosure is possible but remains unproven.

ImportantCandidate is NO because neither substantial sensitive-data recovery nor a stronger exploitation primitive is established. AutoDowngradeAllowed is NO because this is a concrete network-visible kernel disclosure and its repeatability and data sensitivity require review before closure.

5. One-sentence report phrase

An adjacent TIPC peer may receive residual kernel skb bytes in the fixed-length interface-name field of RESET or ACTIVATE messages, creating a bounded but potentially repeatable kernel information disclosure.

6. Manual review recommendation

MANUAL CHECK REQUIRED

Confirm whether an untrusted peer can repeatedly induce the affected messages, how the skb storage is initialized, and whether disclosed padding can contain security-sensitive kernel data.

7. Call-site confidence

Call-site confidence: high

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

Patch: tipc: Dont send random pad bytes in RESET/ACTIVATE messages [ Upstream
Commit: 48033a89356b8ae21a94db70c79bb6fcc91a23c2
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=48033a89356b8ae21a94db70c79bb6fcc91a23c2

Changed files:
  net/tipc/link.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=48033a89356b8ae21a94db70c79bb6fcc91a23c2

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

The original Linux kernel CVE announcement for CVE-2026-98097 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98097

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:N/A:N
  The Best / paranoid CVSS vector: AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
  The Best / paranoid CVSS score: 6.5

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: 4

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: NO
Published priority for this report (same as in Subject): MODERATE REGULAR

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).