CVE-2021-22556

Name: CVE-2021-22556
Creator: NVD / NIST
Published: 2022-05-03T16:15:18.627+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 0.15%

Last modified Jun 17, 2026

CVE-2021-22556 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. The Security Team discovered an integer overflow bug that allows an attacker with code execution to issue memory cache invalidation operations on pages that they don’t own, allowing them to control kernel memory from userspace. We recommend upgrading to kernel version 4.1 or beyond.. EPSS estimates a 0.15% chance of exploitation in the next 30 days.

Description

The Security Team discovered an integer overflow bug that allows an attacker with code execution to issue memory cache invalidation operations on pages that they don’t own, allowing them to control kernel memory from userspace. We recommend upgrading to kernel version 4.1 or beyond.

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

0.15%

4.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Google	Fuchsia	< 4.1

References

https://fuchsia-review.googlesource.com/c/fuchsia/+/570881Issue Tracking, Patch, Third Party Advisory
https://fuchsia.dev/whats-new/release-notes/f4-1Release Notes, Vendor Advisory
https://fuchsia-review.googlesource.com/c/fuchsia/+/570881Issue Tracking, Patch, Third Party Advisory
https://fuchsia.dev/whats-new/release-notes/f4-1Release Notes, Vendor Advisory

Timeline

Published: May 3, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-22556?

How severe is CVE-2021-22556?

CVE-2021-22556 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.15% probability of exploitation in the next 30 days.

How do I fix CVE-2021-22556?

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-2021-22556?

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

Scan your code now

Source: NVD / NIST