CVE-2026-93271

wifi: ath11k: cap out-of-range rx MCS instead of leaving bogus rate

Published Sep 24, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

wifi: ath11k: cap out-of-range rx MCS instead of leaving bogus rate

ath11k can receive HT/VHT/HE frames whose reported MCS is above the
maximum that can be expressed in the corresponding mac80211 rate space
(e.g. an HE frame reported with MCS 12, while HE tops out at MCS 11).

The frame itself is valid and decodes correctly, but for such a frame
ath11k_dp_rx_h_rate() leaves rx_status->rate_idx set to the out-of-range
value and never assigns rx_status->encoding, so it stays RX_ENC_LEGACY
from the ath11k_dp_rx_h_ppdu() initialization. Once that frame reaches
mac80211 it trips the rate sanity check and the frame is dropped with a
splat:

ath11k_pci 0000:03:00.0: Received with invalid mcs in HE mode 12
WARNING: CPU: 0 PID: 0 at net/mac80211/rx.c:5433 ieee80211_rx_list+0xb0a/0xe90 [mac80211]

Dropping the frame would discard otherwise valid data, so instead cap the
reported MCS to the maximum the rate space can express and deliver the
frame. Set rx_status->encoding before the range check and assign rate_idx
from the capped value, so a frame with an out-of-range MCS no longer
leaves partial or bogus rate metadata behind. Also downgrade the logging
level since they are not treated as invalid frames now. The only loss is
that such a frame is reported as the capped MCS in the rx rate statistics.

Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4817-1 linux-6.12 security update
Debian DLA Debian DLA DLA-4841-1 linux security update
Debian DSA Debian DSA DSA-6528-1 linux security update
Ubuntu USN Ubuntu USN USN-8961-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9022-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9023-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9024-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9025-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9026-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9029-1 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-9039-1 Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-9040-1 Linux kernel (Low Latency NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-9066-1 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-9091-1 Linux kernel (NVIDIA Tegra) vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-665
CWE-682
Type Values Removed Values Added
Weaknesses CWE-1284
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Weaknesses CWE-665
CWE-682
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: wifi: ath11k: cap out-of-range rx MCS instead of leaving bogus rate ath11k can receive HT/VHT/HE frames whose reported MCS is above the maximum that can be expressed in the corresponding mac80211 rate space (e.g. an HE frame reported with MCS 12, while HE tops out at MCS 11). The frame itself is valid and decodes correctly, but for such a frame ath11k_dp_rx_h_rate() leaves rx_status->rate_idx set to the out-of-range value and never assigns rx_status->encoding, so it stays RX_ENC_LEGACY from the ath11k_dp_rx_h_ppdu() initialization. Once that frame reaches mac80211 it trips the rate sanity check and the frame is dropped with a splat: ath11k_pci 0000:03:00.0: Received with invalid mcs in HE mode 12 WARNING: CPU: 0 PID: 0 at net/mac80211/rx.c:5433 ieee80211_rx_list+0xb0a/0xe90 [mac80211] Dropping the frame would discard otherwise valid data, so instead cap the reported MCS to the maximum the rate space can express and deliver the frame. Set rx_status->encoding before the range check and assign rate_idx from the capped value, so a frame with an out-of-range MCS no longer leaves partial or bogus rate metadata behind. Also downgrade the logging level since they are not treated as invalid frames now. The only loss is that such a frame is reported as the capped MCS in the rx rate statistics. Tested-on: WCN6855 hw2.1 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41
Title wifi: ath11k: cap out-of-range rx MCS instead of leaving bogus rate
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 9:08 AM
Reserved
Sep 17, 2026, 4:02 PM
Status
Received
Published
Sep 24, 2026, 4:17 PM
Modified
Oct 19, 2026, 10:17 AM
Severity
Moderate
Public date
Sep 24, 2026, 12:00 AM