CVE-2021-1820

Name: CVE-2021-1820
Creator: NVD / NIST
Published: 2021-09-08T15:15:09.993+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.29%

Last modified Jun 17, 2026

CVE-2021-1820 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. A memory initialization issue was addressed with improved memory handling. This issue is fixed in macOS Big Sur 11.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5. EPSS estimates a 1.29% chance of exploitation in the next 30 days.

Description

A memory initialization issue was addressed with improved memory handling. This issue is fixed in macOS Big Sur 11.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5. Processing maliciously crafted web content may result in the disclosure of process memory.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

1.29%

66.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-665

Affected Software

Vendor	Product	Versions
Apple	Ipados	< 14.5
Apple	Iphone Os	< 14.5
Apple	Macos	>= 11.0, < 11.3
Apple	Tvos	< 14.5
Apple	Watchos	< 7.4

References

https://support.apple.com/en-us/HT212317Vendor Advisory
https://support.apple.com/en-us/HT212323Vendor Advisory
https://support.apple.com/en-us/HT212324Vendor Advisory
https://support.apple.com/en-us/HT212325Vendor Advisory
https://support.apple.com/en-us/HT212317Vendor Advisory
https://support.apple.com/en-us/HT212323Vendor Advisory
https://support.apple.com/en-us/HT212324Vendor Advisory
https://support.apple.com/en-us/HT212325Vendor Advisory

Timeline

Published: Sep 8, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-1820?

How severe is CVE-2021-1820?

CVE-2021-1820 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.29% probability of exploitation in the next 30 days.

How do I fix CVE-2021-1820?

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-2021-1820?

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

Scan your code now

Source: NVD / NIST