CVE-2021-1773

Denial of service via image state mishandling

Published Apr 2, 2021 · Updated Aug 3, 2024

Denial of service in Apple ImageIO on iOS and iPadOS before 14.4 and macOS before 11.2 allows attackers to interrupt image processing. ImageIO mishandles internal state while processing a maliciously crafted image, but Apple has not disclosed the erroneous transition or parser path. Exploitation requires local access and user interaction; the reported consequence is application termination or service interruption, not data access or code execution.

CVSS severity5.5
Medium
EPSS probability0.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Apple ImageIO on iOS and iPadOS before 14.4 and macOS before 11.2 allows attackers to interrupt image processing. ImageIO mishandles internal state while processing a maliciously crafted image, but Apple has not disclosed the erroneous transition or parser path. Exploitation requires local access and user interaction; the reported consequence is application termination or service interruption, not data access or code execution.

The record

CVE
CVE-2021-1773
Published
Apr 2, 2021
Updated
Aug 3, 2024
Vendor
Apple
Product
iOS and iPadOS
Classifications
T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 2, 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 <14.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · iOS and iPadOSversion=unspecified <14.4
Apple · macOSversion=unspecified <11.2; version=unspecified <14.4; version=unspecified <7.3

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P

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

T1499Endpoint Denial of Service

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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