CVE-2021-30954

Arbitrary code execution via WebKit type confusion

Published Aug 24, 2021 · Updated Aug 3, 2024

Type confusion in WebKit across affected Apple operating systems allows attackers to execute arbitrary code via malicious web content. Apple has not published the affected WebKit function or incompatible object types, stating only that improved memory handling resolves the confusion. Exploitation requires an affected device to process attacker-controlled web content and yields code execution in the rendering process.

CVSS severity7.8
High
EPSS probability1.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in WebKit across affected Apple operating systems allows attackers to execute arbitrary code via malicious web content. Apple has not published the affected WebKit function or incompatible object types, stating only that improved memory handling resolves the confusion. Exploitation requires an affected device to process attacker-controlled web content and yields code execution in the rendering process.

The record

CVE
CVE-2021-30954
Published
Aug 24, 2021
Updated
Aug 3, 2024
Vendor
Apple
Product
iOS and iPadOS
Classifications
CWE-843, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 24, 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 <15.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · iOS and iPadOSversion=unspecified <15.2
Apple · macOSversion=unspecified <12.1; version=unspecified <15.2
Apple · watchOSversion=unspecified <8.3

Published CVSS scores

9.3NIST NVDAV:N/AC:M/Au:N/C:C/I:C/A:C
7.8NIST NVDCVSS: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.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')
T1203Exploitation for Client Execution

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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