CVE-2021-30771

Arbitrary code execution via malformed font parsing

Published Mar 18, 2022 · Updated Aug 3, 2024

Apple macOS before 11.4, iOS, iPadOS, and tvOS before 14.6, and watchOS before 7.5 allow attackers to execute code via a crafted font. FontParser fails to validate input bounds while processing the file, permitting an out-of-bounds write. The victim must cause the device to process the malicious font; successful exploitation executes code in the affected parsing context.

CVSS severity7.8
High
EPSS probability1.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Apple macOS before 11.4, iOS, iPadOS, and tvOS before 14.6, and watchOS before 7.5 allow attackers to execute code via a crafted font. FontParser fails to validate input bounds while processing the file, permitting an out-of-bounds write. The victim must cause the device to process the malicious font; successful exploitation executes code in the affected parsing context.

The record

CVE
CVE-2021-30771
Published
Mar 18, 2022
Updated
Aug 3, 2024
Vendor
Apple
Product
iOS and iPadOS
Classifications
CWE-787, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 18, 2022CVE 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 <14.6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · iOS and iPadOSversion=unspecified <14.6
Apple · tvOSversion=unspecified <14.6
Apple · macOSversion=unspecified <11.4
Apple · watchOSversion=unspecified <7.5

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
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-787Out-of-bounds Write
T1204.002Malicious File

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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