[CVE-2026-46307][MODERATE REGULAR] wifi: ath5k: do not access array OOB

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

CVE: CVE-2026-46307
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: wifi: ath5k: do not access array OOB
Commit: ecb1c163166759dec004c1fdb9709b8a5992fc8e
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ecb1c163166759dec004c1fdb9709b8a5992fc8e
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46307
Analysis date: Mon, 08 Jun 2026 14:34:07 -0400
ActionableScore: 3
ActionableScore lower bound: 2
Actionable bucket: Borderline manual review recommended / Ordinary Moderate
Manual review required: YES

Summary:
An off-by-one OOB write in the ath5k TX completion path can write a fixed sentinel value past the TX rate array into adjacent TX status metadata, with practical impact likely limited to metadata corruption or warning-based DoS on affected ath5k hardware.

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

The original Linux kernel CVE announcement for CVE-2026-46307 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46307

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.

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-46307	MODERATE	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L';*CWE-787;CWE-129;CWE-193;Other CVSS 'AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L';BEST CVSS score: '5';DESCR 'An out of bounds write in the ath5k TX completion path occurs because ts_final_idx can be 3 while ieee80211_tx_info status rates has only 4 entries, and the code writes the idx sentinel at the next entry. The write reaches rates(4) and according to the patch context lands on the adjacent ack_signal status field, so the observed corruption is narrow and mostly limited to TX status metadata. For the CVSS the PR:N is used for the paranoid adjacent network case because a nearby wireless peer may be able to stimulate transmissions and retry behavior without a local account, but reliable triggering depends on ath5k hardware, active WiFi use, and rate retry conditions. The issue is adjacent network reachable rather than Internet reachable because it is tied to local 802.11 radio range and the ath5k device. Impact is at least low integrity or availability impact due to bounded kernel memory corruption and UBSAN warnings, with no strong evidence of arbitrary write or privilege escalation.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline manual review recommended / Ordinary Moderate (with actual score 3) 	MAYBE	REMOTE WRITE KASAN OOB NETWORK LINUS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	-	-	checked

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

ActionableScore=3
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 3
* Final recommended bucket: **Borderline manual review recommended / Ordinary Moderate**::

## 2. Signal breakdown

Triggered signals:

* Firmware-mediated external influence: +1
  The final TX status index comes from ath5k hardware behavior and may be influenced indirectly by wireless transmission and retry conditions, but this is not Internet-reachable remote input.

* Constrained kernel buffer overwrite: +1
  This is a real OOB write, but the write is fixed as `idx = -1` and the commit states it overwrites only the adjacent `ack_signal` field.

* Integrity impact plausible: +1
  The adjacent TX status metadata can be corrupted, although the practical semantic impact appears narrow.

Paranoid-only signal:

* Availability impact realistic: +1
  UBSAN detects the OOB access, and systems configured to panic on warnings or sanitizers may experience a crash. This is not counted in the conservative score because the commit describes the overwrite effect as negligible.

Subtracting signals:

* Corruption primitive highly constrained or metadata-only: -1
  The overwrite target is adjacent metadata, not attacker-selected memory, and the payload is a fixed sentinel value.

* Rare hardware-specific condition: -1
  The issue depends on ath5k hardware and the 5212 TX status behavior, so exposure is narrower than common networking core paths.

## 3. Reachability analysis

A nearby wireless peer may be able to influence retry and acknowledgement behavior, but the vulnerable write occurs in the local ath5k TX completion path and depends on device-specific hardware status. No local user account is necessarily required in the most paranoid adjacent-network interpretation, but reliable triggering still requires an affected ath5k device, active WiFi transmission, and the hardware producing `ts_final_idx == 3`.

This is not a normal remote network vulnerability over TCP/IP. It is adjacent-radio and hardware-dependent. Namespaces and containers do not materially lower the privilege requirement because the vulnerable path is in the host wireless driver and depends on physical WiFi device activity rather than a delegated local kernel API.

## 4. Severity interpretation

This behaves more like an ordinary Moderate or borderline manual-review issue than an Important-class vulnerability. The bug is real kernel memory corruption, but the corruption is tightly bounded: a fixed value is written one element past a four-entry TX rate array and lands in the adjacent `ack_signal` field. There is no evidence of attacker-controlled target selection, arbitrary write, UAF, reclaim primitive, object confusion, or privilege escalation path.

Theoretical memory-corruption concern justifies manual review, but realistic exploitation evidence supports only low integrity impact and possible sanitizer or warning-based DoS under specific hardware conditions.

## 5. One-sentence report phrase

An off-by-one OOB write in the ath5k TX completion path can write a fixed sentinel value past the TX rate array into adjacent TX status metadata, with practical impact likely limited to metadata corruption or warning-based DoS on affected ath5k hardware.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Reason: this is a real OOB write in kernel memory, but the overwrite is fixed, adjacent, metadata-only, and described by the patch as negligible, so it should be reviewed but does not look like an Important candidate from the available evidence.

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

Patch: wifi: ath5k: do not access array OOB
Commit: ecb1c163166759dec004c1fdb9709b8a5992fc8e
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ecb1c163166759dec004c1fdb9709b8a5992fc8e

Commit description:

Vincent reports:
> The ath5k driver seems to do an array-index-out-of-bounds access as
> shown by the UBSAN kernel message:
> UBSAN: array-index-out-of-bounds in drivers/net/wireless/ath/ath5k/base.c:1741:20
> index 4 is out of range for type 'ieee80211_tx_rate [4]'
> ...
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x5d/0x80
>  ubsan_epilogue+0x5/0x2b
>  __ubsan_handle_out_of_bounds.cold+0x46/0x4b
>  ath5k_tasklet_tx+0x4e0/0x560 [ath5k]
>  tasklet_action_common+0xb5/0x1c0

It is real. 'ts->ts_final_idx' can be 3 on 5212, so:
   info->status.rates[ts->ts_final_idx + 1].idx = -1;
with the array defined as:
   struct ieee80211_tx_rate rates[IEEE80211_TX_MAX_RATES];
while the size is:
   #define IEEE80211_TX_MAX_RATES  4
is indeed bogus.

Set this 'idx = -1' sentinel only if the array index is less than the
array size. As mac80211 will not look at rates beyond the size
(IEEE80211_TX_MAX_RATES).

Note: The effect of the OOB write is negligible. It just overwrites the
next member of info->status, i.e. ack_signal.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Reported-by: Vincent Danjean <vdanjean@debian.org>
Link: https://lore.kernel.org/all/aQYUkIaT87ccDCin@eldamar.lan
Closes: https://bugs.debian.org/1119093
Fixes: 6d7b97b ("ath5k: fix tx status reporting issues")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251209100459.2253198-1-jirislaby@kernel.org
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/ath5k/base.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=ecb1c163166759dec004c1fdb9709b8a5992fc8e

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

The original Linux kernel CVE announcement for CVE-2026-46307 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46307

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:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L
  The Best / paranoid CVSS vector: AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
  The Best / paranoid CVSS score: 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: 2
  Paranoid ActionableScore: 3

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).