CVE-2021-32537Public exploit

System crash via unchecked IOCTL array index

Published Jul 7, 2021 · Updated Sep 17, 2024

Out-of-bounds access in RTKVHD64.sys versions 8155 through 9150 allows local users to crash Windows via a crafted IOCTL request. The driver's 0x225f04 IOCTL handler uses the first input DWORD as an unchecked index into a 63-element EVT array, then passes an out-of-bounds pointer to KeAcquireSpinLockRaiseToDpc. Low-privileged local access is required; successful exploitation corrupts kernel-pool addressing and produces a system crash, with no reported confidentiality or integrity impact.

CVSS severity6.5
Medium
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds access in RTKVHD64.sys versions 8155 through 9150 allows local users to crash Windows via a crafted IOCTL request. The driver's 0x225f04 IOCTL handler uses the first input DWORD as an unchecked index into a 63-element EVT array, then passes an out-of-bounds pointer to KeAcquireSpinLockRaiseToDpc. Low-privileged local access is required; successful exploitation corrupts kernel-pool addressing and produces a system crash, with no reported confidentiality or integrity impact.

The record

CVE
CVE-2021-32537
Published
Jul 7, 2021
Updated
Sep 17, 2024
Vendor
Realtek Semiconductor Corp.
Product
Realtek High Definition Audio Driver
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=8155 <=9150

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Realtek Semiconductor Corp. · Realtek High Definition Audio Driverversion=8155 <=9150

Published CVSS scores

6.5TWCERT/CCCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitPublished

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo