[CVE-2026-68387][LOW] can: raw: add locking for raw flags bitfield [ Upstream

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

CVE: CVE-2026-68387
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: can: raw: add locking for raw flags bitfield [ Upstream
Commit: 00ba4bf8798242253fefc1fa6a78db1d445fd024
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=00ba4bf8798242253fefc1fa6a78db1d445fd024
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68387
Analysis date: Mon, 10 Aug 2026 11:32:17 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A local race in CAN_RAW setsockopt() bitfield updates can cause lost option updates or inconsistent socket state, but the patch does not show memory corruption, privilege escalation, or remote reachability.

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

The original Linux kernel CVE announcement for CVE-2026-68387 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68387

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: LOW
Manual review required: NO

A detailed explanation of the methodology and priority rules is included
at the end of this message.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-68387	LOW	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L';CWE-362;CWE-667;CWE-662;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '3.6';DESCR 'A race in CAN_RAW socket option handling can occur because bitfield flag updates in raw_setsockopt() are read-modify-write operations without serialization. Concurrent local setsockopt() calls on the same socket may lose updates or leave the socket with an unexpected option state. For the CVSS the PR:L is used because reliable triggering requires local code that can operate on a CAN_RAW socket. This may be an unprivileged local process on permissive systems or a reduced capability process with CAP_NET_RAW rather than full administrator rights. The issue is not network reachable because packet traffic does not invoke the vulnerable control path. Impact is low and is limited to local socket state corruption or denial of service for the affected CAN_RAW communication path. No UAF, OOB access, NULL dereference, or arbitrary write primitive is indicated by the patch context.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)  SKIP CVE-2026-68387 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 890e5198a6e5b238627c245fafea1a92670a86cd YES  NO NO unknown 	MAYBE	LOCK DANGER INIT LINUS  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=2
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**

## 2. Signal breakdown

Triggered signals:

* Local low-privilege trigger: +1
  A local process that can operate on a CAN_RAW socket can call setsockopt() concurrently on the same socket. This is PR:L style reachability, not remote reachability.

* Integrity impact plausible: +1 in paranoid score only
  The race can lose bitfield updates and leave CAN_RAW socket options in an unexpected state. This is limited socket configuration integrity, not kernel memory integrity.

Subtracted or not awarded:

* Hard or unreliable race / special timing required: -1
  The issue depends on concurrent read-modify-write flag updates.

* Generic memory corruption: +0
  The patch does not indicate UAF, OOB access, double free, type confusion, arbitrary write, NULL dereference, or stale lifetime corruption.

* Privilege escalation plausible: +0
  No reclaim primitive, overwrite primitive, callback control, refcount abuse, or object confusion is shown.

* Reliable kernel crash / strong DoS: +0
  The demonstrated consequence is inconsistent socket option state, not a reliable system-wide crash.

* Remote reachable / network-triggerable: +0
  Packet traffic does not invoke the vulnerable raw_setsockopt() control path.

## 3. Reachability analysis

The bug is triggered locally through concurrent setsockopt() operations on a CAN_RAW socket. In typical deployments this requires a local process with permission to create or use CAN_RAW sockets, commonly CAP_NET_RAW or an equivalent delegated capability, but not full host root. Namespaces or containers may matter if CAP_NET_RAW is delegated, but the issue still remains local and control-plane only.

The path is not network reachable. CAN traffic itself does not directly trigger the race. CAN support is not as broad as core TCP/IP networking, but where SocketCAN is enabled the interface is reachable through ordinary local socket APIs.

Call-site confidence: high. The patch directly shows raw_setsockopt() wrapping all option handling with rtnl_lock() and lock_sock().

## 4. Severity interpretation

This behaves more like an ordinary Moderate or Low-like correctness/security-hardening issue than an Important vulnerability. Theoretical impact is limited to inconsistent CAN_RAW socket option state due to lost concurrent bitfield updates. Realistic exploitation evidence does not support memory corruption, privilege escalation, sensitive data disclosure, or a reliable kernel crash.

## 5. One-sentence report phrase

A local race in CAN_RAW setsockopt() bitfield updates can cause lost option updates or inconsistent socket state, but the patch does not show memory corruption, privilege escalation, or remote reachability.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

Reason: this is a local race in socket option state handling with no demonstrated memory corruption primitive, no network trigger, no LPE path, and only low local impact.

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

Patch: can: raw: add locking for raw flags bitfield [ Upstream
Commit: 00ba4bf8798242253fefc1fa6a78db1d445fd024
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=00ba4bf8798242253fefc1fa6a78db1d445fd024

Changed files:
  net/can/isotp.c
  net/can/raw.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=00ba4bf8798242253fefc1fa6a78db1d445fd024

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

The original Linux kernel CVE announcement for CVE-2026-68387 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68387

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:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L
  The Best / paranoid CVSS score: 3.6

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: 1
  Paranoid ActionableScore: 2

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: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

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).