CVE-2021-30984Network attack vector

Code execution via WebKit race condition

Published Aug 24, 2021 · Updated Aug 3, 2024

A WebKit race condition in Apple iOS, iPadOS, macOS, and watchOS allows remote attackers to execute code via malicious web content. Apple identifies incorrect state handling in WebKit but has not published the affected function, shared state, or race sequence. Exploitation requires WebKit to process attacker-controlled web content and user interaction; successful exploitation runs arbitrary code in the compromised WebKit context.

CVSS severity7.5
High
EPSS probability1.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A WebKit race condition in Apple iOS, iPadOS, macOS, and watchOS allows remote attackers to execute code via malicious web content. Apple identifies incorrect state handling in WebKit but has not published the affected function, shared state, or race sequence. Exploitation requires WebKit to process attacker-controlled web content and user interaction; successful exploitation runs arbitrary code in the compromised WebKit context.

The record

CVE
CVE-2021-30984
Published
Aug 24, 2021
Updated
Aug 3, 2024
Vendor
Apple
Product
iOS and iPadOS
Classifications
CWE-362, T1203
Attack vector
network
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 vectornetwork
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

5.1NVDAV:N/AC:H/Au:N/C:P/I:P/A:P
7.5NVDCVSS:3.1/AV:N/AC:H/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
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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