CVE-2021-1811Network attack vector

Process-memory disclosure via crafted font state mishandling

Published Sep 8, 2021 · Updated Aug 3, 2024

Information disclosure in Apple CoreText across affected products allows remote attackers to read process memory through a crafted font. CoreText mishandles internal state while processing untrusted font data; Apple has not disclosed the erroneous transition or affected function. Exploitation requires a target process to handle the font, and the documented consequence is process-memory disclosure without data modification or service interruption.

CVSS severity6.5
Medium
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

Information disclosure in Apple CoreText across affected products allows remote attackers to read process memory through a crafted font. CoreText mishandles internal state while processing untrusted font data; Apple has not disclosed the erroneous transition or affected function. Exploitation requires a target process to handle the font, and the documented consequence is process-memory disclosure without data modification or service interruption.

The record

CVE
CVE-2021-1811
Published
Sep 8, 2021
Updated
Aug 3, 2024
Vendor
Apple
Product
iTunes for Windows
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 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 <12.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apple · iTunes for Windowsversion=unspecified <12.11
Apple · iOS and iPadOSversion=unspecified <14.5
Apple · iCloud for Windowsversion=unspecified <12.3
Apple · tvOSversion=unspecified <14.5
Apple · macOSversion=unspecified <11.3; version=unspecified <2021
Apple · watchOSversion=unspecified <7.4

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:P/I:N/A:N

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

No sourced classifications are available.

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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