CVE-2021-30955Public exploit

Kernel code execution via state-handling race

Published Aug 24, 2021 · Updated Aug 3, 2024

Kernel race condition in macOS before 12.1, iOS and iPadOS before 15.2, and watchOS before 8.3 allows local users to run kernel code through a malicious app. Apple identifies the Kernel component and a race corrected by improved state handling, but has not published the affected function or state transition. Execution requires a locally installed malicious application and can yield kernel-level control; a public iOS proof of concept intentionally crashes the kernel.

CVSS severity7.0
High
EPSS probability4.79%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Kernel race condition in macOS before 12.1, iOS and iPadOS before 15.2, and watchOS before 8.3 allows local users to run kernel code through a malicious app. Apple identifies the Kernel component and a race corrected by improved state handling, but has not published the affected function or state transition. Execution requires a locally installed malicious application and can yield kernel-level control; a public iOS proof of concept intentionally crashes the kernel.

The record

CVE
CVE-2021-30955
Published
Aug 24, 2021
Updated
Aug 3, 2024
Vendor
Apple
Product
iOS and iPadOS
Classifications
CWE-362, T1068
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

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=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

7.0NIST National Vulnerability DatabaseCVSS:3.1/AV:L/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1068Exploitation for Privilege Escalation

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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