CVE-2021-30807Known exploitationPublic exploit

Kernel code execution via unchecked framebuffer index

Published Oct 19, 2021 · Updated Oct 21, 2025

Memory corruption in IOMobileFrameBuffer in Apple macOS Big Sur before 11.5.1 allows local users to execute code with kernel privileges. The IOMobileFramebufferUserClient::s_displayed_fb_surface method uses a user-provided index without checking it against the IOSurface pointer array, causing an out-of-bounds pointer read and kernel type confusion. Exploitation requires local application execution, and successful exploitation grants control at kernel privilege.

CVSS severity7.8
High
EPSS probability28.84%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in IOMobileFrameBuffer in Apple macOS Big Sur before 11.5.1 allows local users to execute code with kernel privileges. The IOMobileFramebufferUserClient::s_displayed_fb_surface method uses a user-provided index without checking it against the IOSurface pointer array, causing an out-of-bounds pointer read and kernel type confusion. Exploitation requires local application execution, and successful exploitation grants control at kernel privilege.

The record

CVE
CVE-2021-30807
Published
Oct 19, 2021
Updated
Oct 21, 2025
Vendor
Apple
Product
macOS
Classifications
CWE-787, T1068
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2021Exploitation reportedCISA Known Exploited Vulnerabilities entry
  3. Oct 21, 2025Record 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 <11.5
  2. Affected versionversion=unspecified <14.7
  3. Affected versionversion=unspecified <7.6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · macOSversion=unspecified <11.5; version=unspecified <14.7; version=unspecified <7.6

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
9.3NIST NVDAV:N/AC:M/Au:N/C:C/I:C/A:C
7.8CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/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
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

Public exploit references

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

Reported exploitation

Technologies

Your stack

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Your stack

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