CVE-2021-1857: A memory initialization issue was addressed with improved memory handling

Q: How do I fix CVE-2021-1857?

icloud: upgrade to 12.3; itunes: upgrade to 12.11.3; ipados: upgrade to 14.5. Exact commands for each OS are on this page.

Q: Is CVE-2021-1857 being exploited?

CVE-2021-1857 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-1857 affect?

CVE-2021-1857 affects icloud, itunes, ipados. Severity is medium (CVSS 6.5). A memory initialization issue was addressed with improved memory handling. This issue is fixed in iTunes 12.11.3 for Windows, Security Update 2021-002 Catalina, Security Update 2021-003 Mojave, iCloud for Windows 12.3, macOS Big Sur 11.3, w

Q: How urgent is CVE-2021-1857?

Priority 40/100. No elevated risk signals yet.

This month

MEDIUM 6.5UPGRADEUPGRADEUPGRADE

CVE-2021-1857 is a medium-severity flaw (CVSS 6.5) affecting icloud, itunes, ipados. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A memory initialization issue was addressed with improved memory handling. This issue is fixed in iTunes 12.11.3 for Windows, Security Update 2021-002 Catalina, Security Update 2021-003 Mojave, iCloud for Windows 12.3, macOS Big Sur 11.3, watchOS 7.4, tvOS 14.5, iOS 14.5 and iPadOS 14.5. Processing maliciously crafted web content may disclose sensitive user information.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.2% (top 31%)
CISA exploited list	No
Weakness	CWE-665
Published	2021-09-08
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

2021-09-08 15:15 UTCPublished CVE record published
2026-06-17 03:32 UTCUpdated Record last modified

apple icloud UPGRADE

Affected: < 12.3

Fixed in: 12.3

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 12.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade icloud

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade icloud

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

apple itunes UPGRADE

Affected: < 12.11.3

Fixed in: 12.11.3

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 12.11.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade itunes

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade itunes

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

apple ipados UPGRADE

Affected: < 14.5

Fixed in: 14.5

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: < 14.5

Fixed in: 14.5

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 mac os x MITIGATE

Affected: 10.14 · 10.14.0 · 10.14.1 · 10.14.2 · 10.14.3 · 10.14.4 · 10.14.4 beta4 · 10.14.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.14

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 < 11.3

Fixed in: 11.3

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.

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-2021-1857?

icloud: upgrade to 12.3; itunes: upgrade to 12.11.3; ipados: upgrade to 14.5. Exact commands for each OS are on this page.

Is CVE-2021-1857 being exploited?

CVE-2021-1857 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-2021-1857 affect?

CVE-2021-1857 affects icloud, itunes, ipados. Severity is medium (CVSS 6.5). A memory initialization issue was addressed with improved memory handling. This issue is fixed in iTunes 12.11.3 for Windows, Security Update 2021-002 Catalina, Security Update 2021-003 Mojave, iCloud for Windows 12.3, macOS Big Sur 11.3, w

How urgent is CVE-2021-1857?

Priority 40/100. No elevated risk signals yet.

Software pages

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

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References

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