CVE-2021-47135

Kernel disclosure or panic via unchecked rate index

Published Mar 15, 2024 · Updated Aug 5, 2026

Out-of-bounds read in the Linux kernel mt7921 Wi-Fi driver 5.12 through 5.12.9 allows local users to expose kernel memory or panic the host. The mt7921_mcu_tx_rate_report function uses a firmware-supplied 8-bit rate_idx to index an eight-entry rate array without validating the index. An unprivileged local user must generate traffic on an already-associated mt7921 client interface; derived data can surface through station statistics, while a large index can fault the kernel.

CVSS severity7.8
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in the Linux kernel mt7921 Wi-Fi driver 5.12 through 5.12.9 allows local users to expose kernel memory or panic the host. The mt7921_mcu_tx_rate_report function uses a firmware-supplied 8-bit rate_idx to index an eight-entry rate array without validating the index. An unprivileged local user must generate traffic on an already-associated mt7921 client interface; derived data can surface through station statistics, while a large index can fault the kernel.

The record

CVE
CVE-2021-47135
Published
Mar 15, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-129, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 15, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1c099ab44727c8e42fe4de4d91b53cec3ef02860 <6919e8a24e70b6ba148fe07f44f835bcdd1a8d02
  2. Affected versionversion=1c099ab44727c8e42fe4de4d91b53cec3ef02860 <d874e6c06952382897d35bf4094193cd44ae91bd
  3. Affected versionversion=5.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1c099ab44727c8e42fe4de4d91b53cec3ef02860 <6919e8a24e70b6ba148fe07f44f835bcdd1a8d02; version=1c099ab44727c8e42fe4de4d91b53cec3ef02860 <d874e6c06952382897d35bf4094193cd44ae91bd; version=5.12

Published CVSS scores

7.8NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8Linux Kernel CVE TeamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-129Improper Validation of Array Index
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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