CVE-2020-27931

Arbitrary code execution via malformed font parsing

Published Apr 2, 2021 · Updated Aug 4, 2024

Memory corruption in Apple iOS, iPadOS, macOS, tvOS, and watchOS allows attackers to execute code through a crafted font file. FontParser inadequately validates font-file input, causing memory corruption during parsing; Apple has not disclosed the exact faulty operation. Exploitation requires an affected device to process an attacker-controlled font and can execute code in the context of the parsing process.

CVSS severity7.8
High
EPSS probability0.99%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Apple iOS, iPadOS, macOS, tvOS, and watchOS allows attackers to execute code through a crafted font file. FontParser inadequately validates font-file input, causing memory corruption during parsing; Apple has not disclosed the exact faulty operation. Exploitation requires an affected device to process an attacker-controlled font and can execute code in the context of the parsing process.

The record

CVE
CVE-2020-27931
Published
Apr 2, 2021
Updated
Aug 4, 2024
Vendor
Apple
Product
iOS and iPadOS
Classifications
CWE-787, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 <14.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · iOS and iPadOSversion=unspecified <14.0
Apple · tvOSversion=unspecified <14.0
Apple · macOSversion=unspecified <11.0; version=unspecified <11.1
Apple · watchOSversion=unspecified <7.0

Published CVSS scores

6.8NIST National Vulnerability DatabaseAV:N/AC:M/Au:N/C:P/I:P/A:P
7.8NIST National Vulnerability DatabaseCVSS: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
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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