[CVE-2026-68191][LOW] wifi: ath12k: fix NULL pointer dereference in rhash table destroy

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

CVE: CVE-2026-68191
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: wifi: ath12k: fix NULL pointer dereference in rhash table destroy
Commit: 17a4298f7794843af0094035723dc5e7311c7453
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=17a4298f7794843af0094035723dc5e7311c7453
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68191
Analysis date: Mon, 10 Aug 2026 12:58:47 -0400
ActionableScore: 1
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
ath12k cleanup may call rhashtable_destroy() on uninitialized hash table pointers after failed device initialization or driver unbind, causing a local privileged kernel crash without evidence of confidentiality, integrity, or privilege escalation impact.

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

The original Linux kernel CVE announcement for CVE-2026-68191 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68191

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-2026-68191	LOW	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';**CWE-476;CWE-703;CWE-754;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'ath12k cleanup can call rhashtable_destroy() for link station or link peer hash tables that were never initialized after a failed device start or partial init path. This can dereference a NULL pointer in rhashtable_destroy() or irq_work_sync() during driver unbind or PCI remove and can crash the kernel. For the CVSS the PR:L is used for the paranoid score because some deployments may delegate device reset or driver control to a less trusted local service or reduced capability administrator, although the typical host case is PR:H. The issue is not network reachable through WiFi traffic and requires local control over the driver lifecycle or a failing device initialization path. Impact is denial of service only, with no supported confidentiality or integrity primitive from the patch context.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1)  SKIP CVE-2026-68191 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 57ccca410237285f8f25a988655e6910cadc63f2 YES  NO NO unknown 	MAYBE	REMOTE LOCK NULLPTR NETWORK HARDWARE LINUS  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=1
ActionableScoreLower=0

## 1. ActionableScore

* Conservative score: 0
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Conservative signals:

* Reliable kernel crash / strong DoS: +1. The commit provides concrete NULL pointer dereference traces through `rhashtable_destroy()` and `irq_work_sync()` during driver unbind or PCI remove.
* Requires admin/root/CAP_* in typical deployments: -2. Triggering the vulnerable path normally requires driver unbind, PCI remove, device reset, or equivalent host device lifecycle control.
* Rare AND difficult-to-reach subsystem/configuration: -1. The issue is specific to ath12k cleanup paths and requires a partially initialized or failed device start state.

Conservative total is effectively floored at 0.

Paranoid adjustment:

* Use reduced privilege penalty instead of full admin penalty in delegated environments: +1 relative to conservative. Some deployments may expose device reset or driver lifecycle operations to a less trusted local service, VM management layer, or reduced capability administrator, but this is not the normal host default.

No added signals:

* No remote reachable signal. The bug is not triggered by WiFi traffic.
* No generic memory corruption signal. This is a NULL pointer dereference, not UAF, double free, OOB write, type confusion, or refcount corruption.
* No privilege escalation signal. The patch and trace show crash behavior only.
* No confidentiality or integrity impact. There is no readback, overwrite, stale object reuse, or attacker-controlled reclaim primitive.

## 3. Reachability analysis

The realistic trigger is local and privileged: unbinding/removing the ath12k PCI driver or forcing cleanup after a failed initialization path. The commit notes that the issue is reproducible in a VM because MSI addressing initialization fails, but that is still a device or environment failure condition followed by cleanup, not a network-triggerable attack path.

Namespaces and containers normally do not make this reachable unless device management, PCI control, or driver lifecycle operations are explicitly delegated. In such delegated environments the practical privilege level may be closer to PR:L, but the impact remains DoS-only.

The path is not broadly default-exposed. It requires affected ath12k hardware or a VM/device configuration that reaches the failed initialization cleanup path.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like kernel DoS issue. The failure mode is a reliable NULL pointer dereference in a privileged driver cleanup path. There is no supported evidence of memory corruption beyond invalid NULL dereference, no object lifetime reuse, no attacker-controlled payload, and no plausible LPE primitive from the supplied patch context.

The paranoid score is only slightly higher because delegated device-management models can reduce the effective privilege requirement, not because the impact class changes.

## 5. One-sentence report phrase

ath12k cleanup may call rhashtable_destroy() on uninitialized hash table pointers after failed device initialization or driver unbind, causing a local privileged kernel crash without evidence of confidentiality, integrity, or privilege escalation impact.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be auto-closed for practical triage unless the evaluated product delegates ath12k PCI/device lifecycle control to untrusted users or service accounts.

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

Patch: wifi: ath12k: fix NULL pointer dereference in rhash table destroy
Commit: 17a4298f7794843af0094035723dc5e7311c7453
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=17a4298f7794843af0094035723dc5e7311c7453

Commit description:

When unbinding the ath12k driver, kernel NULL pointer dereferences
occur in irq_work_sync() called from rhashtable_destroy().

Two hash tables are affected:
1. ath12k_link_sta hash table in ath12k_base
2. ath12k_dp_link_peer hash table in ath12k_dp

The issue happens because the destroy functions are called unconditionally
in cleanup paths, but the hash tables are only initialized late in their
respective init functions. If the device was never fully started or if the
init functions failed before initializing the hash tables, the pointers
will be NULL. The issues are always reproducible from a VM because the MSI
addressing initialization is failing.

Call trace for ath12k_link_sta_rhash_tbl_destroy:
 RIP: irq_work_sync+0x1e/0x70
 rhashtable_destroy+0x12/0x60
 ath12k_link_sta_rhash_tbl_destroy+0x19/0x40 [ath12k]
 ath12k_core_stop+0xe/0x80 [ath12k]
 ath12k_core_hw_group_cleanup+0x6b/0xb0 [ath12k]
 ath12k_pci_remove+0x60/0x110 [ath12k]

Call trace for ath12k_dp_link_peer_rhash_tbl_destroy:
 RIP: irq_work_sync+0x1e/0x70
 rhashtable_destroy+0x12/0x60
 ath12k_dp_link_peer_rhash_tbl_destroy+0x29/0x50 [ath12k]
 ath12k_dp_cmn_device_deinit+0x21/0x140 [ath12k]
 ath12k_core_hw_group_cleanup+0x6b/0xb0 [ath12k]
 ath12k_pci_remove+0x60/0x110 [ath12k]

Fix this by adding NULL checks before calling rhashtable_destroy() in
both destroy functions.

The NULL check approach was chosen because the rhashtable pointer
serves as the initialization state indicator. The init can fail at
various points, leaving some components uninitialized. Checking the
pointer directly is simpler than adding separate state flags that
would need synchronization.

Fixes: 57ccca4 ("wifi: ath12k: Add hash table for ath12k_link_sta in ath12k_base")
Fixes: a88cf5f ("wifi: ath12k: Add hash table for ath12k_dp_link_peer")
Cc: stable@vger.kernel.org
Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Link: https://patch.msgid.link/20260615112103.601982-1-jtornosm@redhat.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/net/wireless/ath/ath12k/dp_peer.c
  drivers/net/wireless/ath/ath12k/peer.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=17a4298f7794843af0094035723dc5e7311c7453

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

The original Linux kernel CVE announcement for CVE-2026-68191 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68191

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:H/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:N/I:N/A:H
  The Best / paranoid CVSS score: 5.5

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: 0
  Paranoid ActionableScore: 1

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).