CVE-2021-1789

Name: CVE-2021-1789
Creator: NVD / NIST
Published: 2021-04-02T18:15:21.747+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10Actively ExploitedEPSS 14.54%

Last modified Jun 17, 2026

CVE-2021-1789 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. A type confusion issue was addressed with improved state handling. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, tvOS 14.4, watchOS 7.3, iOS 14.4 and iPadOS 14.4, Safari 14.0.3. CISA has confirmed active exploitation in the wild. EPSS estimates a 14.54% chance of exploitation in the next 30 days.

Description

A type confusion issue was addressed with improved state handling. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, tvOS 14.4, watchOS 7.3, iOS 14.4 and iPadOS 14.4, Safari 14.0.3. Processing maliciously crafted web content may lead to arbitrary code execution.

Metrics

CVSS 3.1

8.8/10

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

EPSS Probability

14.54%

96.2th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by May 25, 2022.

Weakness Enumeration

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
Fedoraproject	Fedora	32
Fedoraproject	Fedora	33
Webkitgtk	Webkitgtk	< 2.30.6

References

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JN6ZOD62CTO54CHTMJTHVEF6R2Y532TJ/Broken Link, Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/Broken Link, Mailing List
https://security.gentoo.org/glsa/202104-03Third Party 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
https://support.apple.com/en-us/HT212152Release Notes, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JN6ZOD62CTO54CHTMJTHVEF6R2Y532TJ/Broken Link, Mailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/Broken Link, Mailing List
https://security.gentoo.org/glsa/202104-03Third Party 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
https://support.apple.com/en-us/HT212152Release Notes, Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1789US Government Resource

Timeline

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

Frequently Asked Questions

What is CVE-2021-1789?

How severe is CVE-2021-1789?

CVE-2021-1789 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 14.54% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2021-1789?

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-2021-1789?

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

Scan your code now

Source: NVD / NIST