CVE-2021-1738

Arbitrary code execution via out-of-bounds image write

Published Apr 2, 2021 · Updated Aug 3, 2024

Out-of-bounds write in ImageIO in Apple macOS allows attackers to execute arbitrary code by processing a maliciously crafted image. ImageIO writes beyond allocated memory while processing image data that has not been adequately validated. Exploitation requires user interaction; Apple has not identified the image format or the affected parsing routine.

CVSS severity7.8
High
EPSS probability0.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds write in ImageIO in Apple macOS allows attackers to execute arbitrary code by processing a maliciously crafted image. ImageIO writes beyond allocated memory while processing image data that has not been adequately validated. Exploitation requires user interaction; Apple has not identified the image format or the affected parsing routine.

The record

CVE
CVE-2021-1738
Published
Apr 2, 2021
Updated
Aug 3, 2024
Vendor
Apple
Product
macOS
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 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <11.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · macOSversion=unspecified <11.2

Published CVSS scores

6.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
7.8NVDCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo