What is CVE-2021-22556?

CVE-2021-22556 is a medium-severity vulnerability in Google Fuchsia, classified under Integer Overflow or Wraparound. CVSS score: 5.3/10. Published 2022-05-03.

How severe is CVE-2021-22556?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Integer overflow in Google Fuchsia

CVE-2021-22556

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.

Vulnerability class: Integer Overflow

Published 2022-05-03 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (5.0th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 5th percentile — 5.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Google Fuchsia
Google Llc Fuchsia Kernel — versions unspecified

Weakness classification (CWE)

CWE-190 — Integer Overflow or Wraparound

References

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

Frequently asked questions

What is CVE-2021-22556?: CVE-2021-22556 is a medium-severity vulnerability in Google Fuchsia, classified under Integer Overflow or Wraparound. CVSS score: 5.3/10. Published 2022-05-03.
How severe is CVE-2021-22556?: Medium severity. CVSS v3 base score is 5.3 out of 10.