[CVE-2026-53225][MODERATE REGULAR] sctp: fix uninit-value in __sctp_rcv_asconf_lookup() [ Upstream

[CVE-2026-53225][MODERATE REGULAR] sctp: fix uninit-value in __sctp_rcv_asconf_lookup() [ Upstream

[AL-KERNEL]

CVE: CVE-2026-53225
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: sctp: fix uninit-value in __sctp_rcv_asconf_lookup() [ Upstream
Commit: 446e0ecd845abc394b24ae2030a883572bec9d16
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=446e0ecd845abc394b24ae2030a883572bec9d16
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53225
Analysis date: Thu, 25 Jun 2026 10:34:18 -0400
ActionableScore: 4
ActionableScore lower bound: 3
Actionable bucket: Borderline, manual review recommended but not Important
Manual review required: YES

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-53225 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53225

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-2026-53225	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:L';*CWE-457;CWE-125;*CWE-20;Other CVSS 'AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '6.5';DESCR 'A truncated SCTP ASCONF address parameter can reach __sctp_rcv_asconf_lookup with only the parameter header present while af from_addr_param later reads the full address length. A remote SCTP peer can trigger an uninitialized read by sending a malformed trailing ASCONF chunk that declares an IPv6 address parameter but does not include the full address bytes. For the CVSS the PR:N is used for the paranoid score because the packet can be sent by an unauthenticated network peer when SCTP is reachable on the target. The issue is network reachable and does not require local code execution on the victim. Impact is primarily denial of service through sanitizer warning, warning based policy, or undefined lookup behavior. The invalid read touches uninitialized kernel memory, but the patch context does not show a direct disclosure channel or arbitrary write primitive. For the paranoid score, limited confidentiality impact is still defensible because kernel memory is read in the receive path, so manual review is preferred.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended but not Important (with actual score 4)	YES	READ KASAN OOB INIT SIMPLEFIX NETWORK LINUS IPV6  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	NO	NO	checked

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

ActionableScore=4
ActionableScoreLower=3

1. **ActionableScore**

* Conservative score: 3
* Paranoid score: 4
* Final recommended bucket: **Borderline, manual review recommended but not Important**::

2. **Signal breakdown**

* Remote reachable / network-triggerable: +2. An unauthenticated SCTP peer can send a malformed ASCONF chunk.
* Common networking / packet receive path: +1. This is in the SCTP receive-side association lookup path, though SCTP is less commonly exposed than TCP/UDP.
* Confidentiality impact plausible: +1 paranoid only. The bug reads uninitialized kernel memory past a truncated parameter, but no direct user-visible disclosure channel is shown.
* Availability impact: +1 paranoid only. KMSAN or warning-based configurations may turn this into a visible failure, but the patch does not show a reliable production kernel crash.
* Rare or less commonly exposed protocol/configuration: -1. SCTP is not broadly Internet-exposed in typical deployments.

No points for generic memory corruption, UAF, OOB write, LPE, Dirty-Pipe-like behavior, or strong DoS. The primitive is an uninitialized / invalid read only.

3. **Reachability analysis**

The trigger is remote if SCTP is enabled and reachable on the target. No local user account or authentication is required according to the commit message. Containers and namespaces are not central to triggering because the packet can arrive from the network. Realistic exploitation depends strongly on whether SCTP traffic is accepted by firewall policy and whether any SCTP endpoint is exposed. In many deployments SCTP is uncommon or filtered, but in telecom or specialized environments it may be reachable.

4. **Severity interpretation**

This behaves like a **borderline / actionable Moderate** issue, not an Important-class vulnerability based on the patch alone. The theoretical concern is a remote uninitialized kernel-memory read, but the demonstrated primitive is limited to reading up to 16 bytes past a truncated ASCONF address parameter inside kernel receive processing. There is no demonstrated disclosure path, write primitive, UAF, object lifetime corruption, or privilege-escalation path. Manual review is still worthwhile because the bug is remotely reachable and touches uninitialized kernel memory in a network parser.

5. **One-sentence report phrase**

A remote unauthenticated SCTP peer can send a truncated ASCONF address parameter that makes `__sctp_rcv_asconf_lookup()` read uninitialized bytes past the parameter, creating a limited remote invalid-read issue with possible low confidentiality or availability impact depending on configuration.

6. **Manual review recommendation**

**MANUAL CHECK RECOMMENDED**

Reason: network reachability plus uninitialized kernel-memory read deserves review, but current evidence does not justify Important-class handling because there is no concrete leak channel, memory corruption, or LPE primitive.

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

Patch: sctp: fix uninit-value in __sctp_rcv_asconf_lookup() [ Upstream
Commit: 446e0ecd845abc394b24ae2030a883572bec9d16
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=446e0ecd845abc394b24ae2030a883572bec9d16

Changed files:
  net/sctp/input.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=446e0ecd845abc394b24ae2030a883572bec9d16

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

The original Linux kernel CVE announcement for CVE-2026-53225 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53225

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:L
  The Best / paranoid CVSS vector: AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
  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: 3
  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).