CVE-2021-1747

Name: CVE-2021-1747
Creator: NVD / NIST
Published: 2021-04-02T18:15:19.543+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 0.90%

Last modified Jun 17, 2026

CVE-2021-1747 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. An out-of-bounds write was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 and iPadOS 14.4. EPSS estimates a 0.90% chance of exploitation in the next 30 days.

Description

An out-of-bounds write was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 and iPadOS 14.4. Processing maliciously crafted web content may lead to code execution.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS Probability

0.90%

55.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Apple	Ipados	< 14.4
Apple	Iphone Os	< 14.4
Apple	Mac Os X	>= 10.14, < 10.14.6
Apple	Mac Os X	>= 10.15, < 10.15.7
Apple	Mac Os X	10.14.6
Apple	Mac Os X	10.15.7
Apple	Macos	>= 11.0, < 11.2
Apple	Tvos	< 14.4
Apple	Watchos	< 7.3

References

https://support.apple.com/en-us/HT212146Release Notes, Vendor Advisory
https://support.apple.com/en-us/HT212147Release Notes, Vendor Advisory
https://support.apple.com/en-us/HT212148Release Notes, Vendor Advisory
https://support.apple.com/en-us/HT212149Release Notes, Vendor Advisory
https://support.apple.com/en-us/HT212146Release Notes, Vendor Advisory
https://support.apple.com/en-us/HT212147Release Notes, Vendor Advisory
https://support.apple.com/en-us/HT212148Release Notes, Vendor Advisory
https://support.apple.com/en-us/HT212149Release Notes, Vendor Advisory

Timeline

Published: Apr 2, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-1747?

How severe is CVE-2021-1747?

CVE-2021-1747 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.90% probability of exploitation in the next 30 days.

How do I fix CVE-2021-1747?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-1747?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST