CVE-2021-30842

Code execution via malicious dfont processing

Published Oct 19, 2021 · Updated Aug 3, 2024

Code execution in FontParser in Apple macOS Big Sur before 11.6 and Catalina allows context-dependent attackers to run code via a dfont file. FontParser accepts the crafted font during dfont processing, but Apple has not published which parser check is missing or what unsafe operation follows. Exploitation requires a user to process the file, after which code runs with the affected application's privileges.

CVSS severity7.8
High
EPSS probability1.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code execution in FontParser in Apple macOS Big Sur before 11.6 and Catalina allows context-dependent attackers to run code via a dfont file. FontParser accepts the crafted font during dfont processing, but Apple has not published which parser check is missing or what unsafe operation follows. Exploitation requires a user to process the file, after which code runs with the affected application's privileges.

The record

CVE
CVE-2021-30842
Published
Oct 19, 2021
Updated
Aug 3, 2024
Vendor
Apple
Product
macOS
Classifications
T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 19, 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 <11.6
  2. Affected versionversion=unspecified <14.8
  3. Affected versionversion=unspecified <15
  4. Affected versionversion=unspecified <2021
  5. Affected versionversion=unspecified <8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · macOSversion=unspecified <11.6; version=unspecified <14.8; version=unspecified <15; version=unspecified <2021; version=unspecified <8

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

T1204.002User Execution: Malicious 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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