[CVE-2026-53224][MODERATE 7.0] sctp: validate embedded INIT chunk and address list lengths in cookie [ Upstream

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

CVE: CVE-2026-53224
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: sctp: validate embedded INIT chunk and address list lengths in cookie [ Upstream
Commit: 7560afb8cddafd829e709d7ea09230e45a825557
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7560afb8cddafd829e709d7ea09230e45a825557
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53224
Analysis date: Thu, 25 Jun 2026 07:23:49 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
Malformed SCTP COOKIE_ECHO packets can trigger out-of-bounds reads in kernel SCTP cookie and address parsing, causing remote DoS and warranting manual review due to limited potential confidentiality impact from network-reachable OOB reads.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-53224 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53224

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-2026-53224	MODERATE	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H';CWE-125;*CWE-20;CWE-130;Other CVSS 'AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '8.2';DESCR 'A malformed SCTP COOKIE_ECHO can carry an embedded INIT chunk that is shorter than a complete INIT header or can declare a raw address list length that extends beyond the cookie payload. Later SCTP cookie and address parsing may read past the validated cookie data, which can trigger out-of-bounds reads in kernel SCTP code and lead to a remote crash or other availability impact. For the CVSS the PR:N is used because a remote peer can send SCTP COOKIE_ECHO traffic without local code execution or an authenticated user account when the SCTP endpoint is reachable and the vulnerable cookie handling path is exposed. The issue is network reachable over SCTP and does not require user interaction. Impact is at least denial of service via kernel crash. For the paranoid score, limited confidentiality impact is retained because the bug class is out-of-bounds read in a network parser, but no strong integrity or arbitrary write primitive is evident from the code context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5)	YES	OOB INIT NETWORK LINUS KPANIC  KPANIC INCREASED_TO_MODERATE7_BASED_ON_GUESSCVSS	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=5
ActionableScoreLower=4

## 1. ActionableScore

* Conservative score: 4
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Remote reachable / network-triggerable: +2
  A malformed SCTP COOKIE_ECHO can be supplied by a remote SCTP peer when the vulnerable endpoint is reachable.

* Reliable kernel crash / strong DoS: +1
  The described OOB reads occur in kernel SCTP parsing and can plausibly lead to fault, crash, or availability loss.

* Network protocol parser scrutiny: +1
  This is a remotely reachable protocol parsing path in the kernel networking stack, even though SCTP exposure is less common than TCP or UDP.

Paranoid additional signal:

* Confidentiality impact plausible: +1
  The primitive is an out-of-bounds read in a network parser. No concrete disclosure channel is shown, so this is only limited paranoid C impact, not integrity or LPE.

Not awarded:

* No generic strong memory corruption bonus. The patch shows OOB reads, not OOB writes, UAF, double-free, type confusion, or arbitrary write.
* No privilege escalation bonus. There is no reclaim, overwrite, callback, refcount, or object confusion primitive.
* No integrity impact. The patch does not show a write or corruption sink.
* No admin privilege penalty. Triggering is by remote SCTP traffic, not local CAP_NET_ADMIN.

## 3. Reachability analysis

A remote peer can trigger the bug by sending malformed SCTP COOKIE_ECHO data to a reachable SCTP endpoint. PR:N is appropriate because no local account or authenticated user context is needed once the SCTP service path is exposed. The issue is not namespace-dependent for the remote case.

Real-world exposure depends on SCTP being enabled and actually reachable. SCTP is less commonly exposed than TCP or UDP services, but it is a real network protocol path and is used in telecom and some specialized deployments. Cookie authentication disabled is an important condition for the raw address list path, while the truncated embedded INIT validation issue is still part of COOKIE_ECHO parsing.

## 4. Severity interpretation

This is stronger than an ordinary Moderate because it is remotely reachable and affects kernel network parsing. It is not a strong Important candidate by default because the demonstrated primitive is read-only OOB access and DoS, without a shown leak channel, write primitive, UAF, or LPE path.

The conservative interpretation is high-end Moderate / borderline manual review. The paranoid interpretation is Actionable Moderate because limited confidentiality impact is technically defensible for an OOB read in a remote parser, but not enough to claim strong memory corruption or privilege escalation.

## 5. One-sentence report phrase

Malformed SCTP COOKIE_ECHO packets can trigger out-of-bounds reads in kernel SCTP cookie and address parsing, causing remote DoS and warranting manual review due to limited potential confidentiality impact from network-reachable OOB reads.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: the bug is remotely reachable, in kernel networking code, and involves OOB reads from attacker-controlled SCTP cookie structures. Even though the realistic impact is likely DoS, the remote parser context and possible limited C impact make auto-close unsafe.

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

Patch: sctp: validate embedded INIT chunk and address list lengths in cookie [ Upstream
Commit: 7560afb8cddafd829e709d7ea09230e45a825557
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7560afb8cddafd829e709d7ea09230e45a825557

Changed files:
  net/sctp/bind_addr.c
  net/sctp/sm_make_chunk.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=7560afb8cddafd829e709d7ea09230e45a825557

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

The original Linux kernel CVE announcement for CVE-2026-53224 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53224

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:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
  The Best / paranoid CVSS score: 8.2

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: 4
  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).