CVE-2021-30928: A memory corruption issue was addressed with improved input validation

This month

HIGH 7.8UPGRADEUPGRADEUPGRADE

CVE-2021-30928 is a high-severity flaw (CVSS 7.8) affecting ipados, iphone os, macos. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A memory corruption issue was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.6, watchOS 8, tvOS 15, iOS 14.8 and iPadOS 14.8, iOS 15 and iPadOS 15. Processing a maliciously crafted image may lead to arbitrary code execution.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.4% (top 27%)
CISA exploited list	No
Weakness	CWE-787
Published	2021-08-24
Last modified	2026-06-17

Publisher (CNA): Apple Inc. · Vendor: apple

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-08-24 19:15 UTCPublished CVE record published
2026-06-17 03:51 UTCUpdated Record last modified

apple ipados UPGRADE

Affected: < 14.8

Fixed in: 14.8

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

apple iphone os UPGRADE

Affected: < 15.0

Fixed in: 15.0

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

apple macos UPGRADE

Affected: >= 11.0 and < 11.6

Fixed in: 11.6

Safe to downgrade to: a release before 11.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

apple tvos UPGRADE

Affected: < 15.0

Fixed in: 15.0

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

apple watchos UPGRADE

Affected: < 8.0

Fixed in: 8.0

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

apple icloud DOWNGRADE

Affected: 13.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 13.0

1. Check installed version

apt-cache policy icloud || rpm -q icloud || icloud --version

2. No fixed release: DOWNGRADE to a release before 13.0 (Debian / Ubuntu)

apt-cache madison icloud sudo apt install icloud=<VERSION_BEFORE_13.0> sudo apt-mark hold icloud

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list icloud sudo dnf downgrade icloud-<VERSION_BEFORE_13.0> sudo dnf versionlock add icloud

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-30928?

ipados: upgrade to 14.8; iphone os: upgrade to 15.0; macos: upgrade to 11.6. Exact commands for each OS are on this page.

Is CVE-2021-30928 being exploited?

CVE-2021-30928 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-30928 affect?

CVE-2021-30928 affects ipados, iphone os, macos. Severity is high (CVSS 7.8). A memory corruption issue was addressed with improved input validation. This issue is fixed in macOS Big Sur 11.6, watchOS 8, tvOS 15, iOS 14.8 and iPadOS 14.8, iOS 15 and iPadOS 15. Processing a maliciously crafted image may lead to arbitr

How urgent is CVE-2021-30928?

Priority 46/100. High severity

Software pages

iOS vulnerabilities · macOS vulnerabilities · iPadOS vulnerabilities · watchOS vulnerabilities · tvOS vulnerabilities

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References

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