[CVE-2026-74287][MODERATE 7.0] sctp: validate embedded address parameter length [ Upstream

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

CVE: CVE-2026-74287
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: sctp: validate embedded address parameter length [ Upstream
Commit: 06c8bf48505f2fef265931db82d5003d302a347b
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=06c8bf48505f2fef265931db82d5003d302a347b
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74287
Analysis date: Sat, 15 Aug 2026 05:23:36 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
A remote out-of-bounds read in SCTP ADD_IP, DEL_IP, and SET_PRIMARY embedded address parameter parsing can be triggered by malformed INIT or ASCONF traffic, with likely impact of remote DoS and limited confidentiality concern but no demonstrated write or privilege-escalation primitive.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-74287 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74287

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-2026-74287	MODERATE	CHECK WITH IMPACT FROM ORIG NN MODERATE	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-130;*CWE-20;Other CVSS 'AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L';BEST CVSS score: '8.2';DESCR 'An out-of-bounds read in SCTP ADD_IP, DEL_IP, and SET_PRIMARY address parameter parsing can occur because the embedded address parameter length was not checked against the enclosing parameter bounds. A malformed peer can advertise an embedded address length that exceeds the remaining bytes in an INIT or ASCONF parameter, causing later address parsing to read past the validated parameter buffer. For the CVSS the PR:N because a remote peer can send malformed SCTP control data without requiring local access or an authenticated user context. The issue is network reachable on systems that accept SCTP traffic and use the affected INIT or ASCONF processing paths. Impact is mainly remote denial of service and limited confidentiality risk from an out-of-bounds read. Because this is a network reachable kernel parser bug, manual review is recommended.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5)	YES	OOB NETWORK LINUS IPV6 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
  Malformed SCTP INIT or ASCONF parameters can be supplied by a remote peer on systems accepting SCTP traffic.

* Confidentiality impact plausible: +1
  The patch explicitly prevents an out-of-bounds read in kernel SCTP parameter parsing. This supports limited confidentiality concern, but not a proven disclosure primitive.

* Common protocol receive / packet-processing path: +1
  The affected code is in SCTP control-parameter parsing during protocol processing, not a local-only ioctl or admin-only control path.

Paranoid additional signal:

* Reliable kernel crash / strong DoS: +1
  A network-triggered kernel out-of-bounds read in a protocol parser can plausibly lead to kernel fault or crash depending on skb layout and hardening, even though the patch does not show an OOB write or arbitrary corruption primitive.

Not awarded:

* No privilege escalation plausible bonus.
  The patch shows OOB read, not UAF reclaim, OOB write, refcount takeover, callback control, or type confusion.

* No generic strong memory corruption bonus.
  This is read-only OOB parsing, not a demonstrated write or lifetime corruption primitive.

* No integrity impact.
  The patch does not support attacker-controlled modification of kernel data or protocol state beyond malformed input rejection.

## 3. Reachability analysis

A remote peer can trigger the vulnerable path by sending malformed SCTP ADD_IP, DEL_IP, or SET_PRIMARY address parameters where the embedded address parameter length exceeds the enclosing parameter bounds. The INIT path is especially relevant because it can occur early in association setup. ASCONF reachability depends on SCTP dynamic address reconfiguration being used and accepted.

No local privileges are required if the target accepts SCTP traffic from the attacker, so the practical PR interpretation is PR:N. Containers and namespaces do not materially reduce the network-triggered nature unless SCTP exposure is blocked by firewalling or module policy. SCTP is less commonly exposed than TCP or UDP services, but this is still a remotely reachable kernel network parser path when SCTP is enabled and reachable.

## 4. Severity interpretation

This behaves like an actionable Moderate issue, not an ordinary auto-closable Moderate. The realistic primitive is a remote out-of-bounds read with possible kernel crash and limited confidentiality concern. It does not currently justify Important-class treatment because there is no OOB write, UAF, reclaim primitive, type confusion, or demonstrated privilege-escalation path.

The paranoid score is raised because remote kernel protocol parser bugs historically deserve manual review, especially when malformed peer-controlled lengths cross validated buffer boundaries.

## 5. One-sentence report phrase

A remote out-of-bounds read in SCTP ADD_IP, DEL_IP, and SET_PRIMARY embedded address parameter parsing can be triggered by malformed INIT or ASCONF traffic, with likely impact of remote DoS and limited confidentiality concern but no demonstrated write or privilege-escalation primitive.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: this is a network-reachable PR:N kernel protocol parser OOB read, so it should not be auto-closed even though the demonstrated primitive is limited and does not show strong memory corruption or LPE.

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

Patch: sctp: validate embedded address parameter length [ Upstream
Commit: 06c8bf48505f2fef265931db82d5003d302a347b
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=06c8bf48505f2fef265931db82d5003d302a347b

Changed files:
  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=06c8bf48505f2fef265931db82d5003d302a347b

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

The original Linux kernel CVE announcement for CVE-2026-74287 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74287

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:L/I:N/A:L
  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).