[CVE-2026-45959][MODERATE 7.0] crypto: ccp - Fix a crash due to incorrect cleanup usage of kfree [ Upstream

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

CVE: CVE-2026-45959
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: crypto: ccp - Fix a crash due to incorrect cleanup usage of kfree [ Upstream
Commit: 9a3ace9b010ffd8c422c97844ae152f7c53d6b18
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9a3ace9b010ffd8c422c97844ae152f7c53d6b18
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45959
Analysis date: Wed, 27 May 2026 19:23:34 -0400
ActionableScore: 6
ActionableScore lower bound: 4
Actionable bucket: Actionable Moderate at minimum
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-45959 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45959

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: NO

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
======================================================================

CVE-2026-45959	MODERATE	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H';CWE-590;CWE-763;CWE-704;CWE-703;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '6.6';DESCR 'The CCP AES GCM path used __cleanup(kfree) on a local pointer variable, which can pass the address of the stack variable to kfree instead of the heap pointer returned by kzalloc(). A local user able to exercise the CCP crypto path can trigger an invalid free and crash the kernel. For the CVSS the PR:L is used because the trigger requires local access to a crypto operation path such as AF_ALG or another interface using the CCP driver, not network reachability. Impact is primarily denial of service. Limited confidentiality and integrity concern is kept only for the paranoid score because this is an invalid free in a kernel allocator path, but there is no demonstrated controlled arbitrary free or privilege escalation primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 5) 	MAYBE	OOB DANGER INIT SIMPLEFIX KERNEL_PANIC_PLUS_UAF KPANIC 	-	-	checked

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

ActionableScore=6
ActionableScoreLower=4

1. ActionableScore
* Conservative score: 4
* Paranoid score: 6
* Final recommended bucket: **Actionable Moderate at minimum**::

2. Signal breakdown
* Local trigger: +1. A local user may exercise the CCP AES-GCM path via AF_ALG or another crypto API consumer if the CCP driver is available.
* Local high-control kernel data-plane API: +1. Crypto operations can be driven with user-controlled parameters through AF_ALG or related interfaces.
* Memory corruption / invalid free candidate: +2. The bug passes the address of a stack local pointer variable to `kfree()`, causing invalid deallocation.
* Reliable kernel crash / strong DoS: +1. Invalid free of a stack address is expected to crash or trigger allocator hardening checks.
* Availability impact realistic: +1. The realistic minimum impact is local kernel crash.
* Constrained primitive: -1. The freed address is a stack slot created by compiler cleanup semantics, not an attacker-chosen arbitrary pointer.

3. Reachability analysis
The bug is local and depends on reaching `ccp_run_aes_gcm_cmd()` on systems with the AMD CCP crypto driver and AES-GCM operation support. It is not network reachable by itself. Containers matter only if they can access AF_ALG or another interface that routes AES-GCM work to the CCP driver. Exploitation beyond crash is constrained because the invalid `kfree()` target is not directly attacker-controlled.

4. Severity interpretation
This is more than ordinary Moderate because it is an invalid free in a kernel crypto path. However, it is not a clear Important candidate because the invalid free is constrained to a stack variable address and the patch does not demonstrate a controlled arbitrary free, UAF reclaim, or privilege escalation. Realistic impact is local DoS.

5. One-sentence report phrase
The CCP AES-GCM path can use `__cleanup(kfree)` incorrectly and pass a stack variable address to `kfree()`, causing a local invalid-free crash through the crypto API.

6. Manual review recommendation
MANUAL CHECK RECOMMENDED. The bug is an invalid free in a local crypto path, but the target is constrained and no practical LPE primitive is demonstrated.

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

Patch: crypto: ccp - Fix a crash due to incorrect cleanup usage of kfree [ Upstream
Commit: 9a3ace9b010ffd8c422c97844ae152f7c53d6b18
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9a3ace9b010ffd8c422c97844ae152f7c53d6b18

Changed files:
  drivers/crypto/ccp/ccp-ops.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=9a3ace9b010ffd8c422c97844ae152f7c53d6b18

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

The original Linux kernel CVE announcement for CVE-2026-45959 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-45959

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:L/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS score: 6.6

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: 4
  Paranoid ActionableScore: 6

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).