CVE-2021-1878

Name: CVE-2021-1878
Creator: NVD / NIST
Published: 2021-09-08T15:15:12.307+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.77%

Last modified Jun 17, 2026

CVE-2021-1878 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. An integer overflow was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.3, Security Update 2021-002 Catalina, Security Update 2021-003 Mojave. EPSS estimates a 1.77% chance of exploitation in the next 30 days.

Description

An integer overflow was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.3, Security Update 2021-002 Catalina, Security Update 2021-003 Mojave. An attacker in a privileged network position may be able to leak sensitive user information.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

1.77%

75.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-190

Affected Software

Vendor	Product	Versions
Apple	Mac Os X	>= 10.14, <= 10.14.5
Apple	Mac Os X	>= 10.15, <= 10.15.5
Apple	Mac Os X	10.14.6
Apple	Mac Os X	10.15.6
Apple	Mac Os X	10.15.7
Apple	Macos	>= 11.0, < 11.3

References

https://support.apple.com/en-us/HT212325Vendor Advisory
https://support.apple.com/en-us/HT212326Vendor Advisory
https://support.apple.com/en-us/HT212327Vendor Advisory
https://support.apple.com/en-us/HT212325Vendor Advisory
https://support.apple.com/en-us/HT212326Vendor Advisory
https://support.apple.com/en-us/HT212327Vendor Advisory

Timeline

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

Frequently Asked Questions

What is CVE-2021-1878?

How severe is CVE-2021-1878?

CVE-2021-1878 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.77% probability of exploitation in the next 30 days.

How do I fix CVE-2021-1878?

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-2021-1878?

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

Scan your code now

Source: NVD / NIST