CVE-2021-30712Public exploitNetwork attack vector

Remote code execution via uninitialized IOCTL pointer

Published Sep 8, 2021 · Updated Aug 3, 2024

Logic error in Apple macOS smbx allows remote authenticated users to crash smbd or corrupt memory via crafted SMB2 packets. When smb2::extract accepts an IOCTL_REQUEST with inputCount set to zero, it returns success without initializing the request's Buffer pointer, which smbd later dereferences. The issue affects Big Sur, Catalina, and Mojave when file sharing exposes SMB; the demonstrated crash depends on binary layout and configuration.

CVSS severity4.2
Medium
EPSS probability3.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Logic error in Apple macOS smbx allows remote authenticated users to crash smbd or corrupt memory via crafted SMB2 packets. When smb2::extract accepts an IOCTL_REQUEST with inputCount set to zero, it returns success without initializing the request's Buffer pointer, which smbd later dereferences. The issue affects Big Sur, Catalina, and Mojave when file sharing exposes SMB; the demonstrated crash depends on binary layout and configuration.

The record

CVE
CVE-2021-30712
Published
Sep 8, 2021
Updated
Aug 3, 2024
Vendor
Apple
Product
macOS
Classifications
CWE-824, T1210
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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=unspecified <11.4
  2. Affected versionversion=unspecified <2021

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Apple · macOSversion=unspecified <11.4; version=unspecified <2021

Published CVSS scores

4.2Cisco TalosCVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:L

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)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-824Access of Uninitialized Pointer
T1210Exploitation of Remote Services

Public exploit references

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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