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CVE-2021-30661: Apple Multiple Products WebKit Storage Use-After-Free Vulnerability

79
Patch now
HIGH 8.8EXPLOITEDUPGRADEUPGRADEUPGRADE

CVE-2021-30661 is a high-severity flaw (CVSS 8.8) affecting safari, ipados, iphone os, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A use after free issue was addressed with improved memory management. This issue is fixed in Safari 14.1, iOS 12.5.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5, macOS Big Sur 11.3. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..

Why this priority

  • High severity
  • EPSS top 9%: very likely to be exploited
  • Exploited in the wild (CISA KEV)

A fixed release or distro patch exists.

Risk facts

CVSS score8.8 (High)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionRequired
EPSS exploit chance4.5% (top 9%)
CISA exploited listYes, fix due 2021-11-17
WeaknessCWE-416
Published2021-09-08
Last modified2026-06-17
Publisher (CNA): Apple Inc. · Vendor: apple

Share: LinkedIn · X · Reddit

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

Am I affected?

Timeline

apple safari UPGRADE
Affected: < 14.1
Fixed in: 14.1
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy safari || rpm -q safari || safari --version
2. UPGRADE to 14.1 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade safari
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade safari
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: < 12.5.3 · >= 14.0 and < 14.5
Fixed in: 12.5.3, 14.5
Safe to downgrade to: a release before 14.0
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 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.
apple tvos 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 watchos UPGRADE
Affected: < 7.4
Fixed in: 7.4
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.

Exact fixes by distribution

Fedora 46 · librepo · FIXED · 1.21.3-1.fc46 · FEDORA-2026-c502136ca7 · source
sudo dnf upgrade --advisory=FEDORA-2026-c502136ca7
Ubuntu 20.04 · webkit2gtk · FIXED · 2.30.3-0ubuntu0.20.04.1
sudo apt update && sudo apt install --only-upgrade webkit2gtk dpkg --compare-versions "$(dpkg-query -W -f='${Version}' webkit2gtk)" ge "2.30.3-0ubuntu0.20.04.1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 22.04 · webkit2gtk · FIXED · 2.30.3-1
sudo apt update && sudo apt install --only-upgrade webkit2gtk dpkg --compare-versions "$(dpkg-query -W -f='${Version}' webkit2gtk)" ge "2.30.3-1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 24.04 · webkit2gtk · FIXED · 2.30.3-1
sudo apt update && sudo apt install --only-upgrade webkit2gtk dpkg --compare-versions "$(dpkg-query -W -f='${Version}' webkit2gtk)" ge "2.30.3-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 12 · webkit2gtk · FIXED · 2.30.1-1
sudo apt update && sudo apt install --only-upgrade webkit2gtk dpkg --compare-versions "$(dpkg-query -W -f='${Version}' webkit2gtk)" ge "2.30.1-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · webkit2gtk · FIXED · 2.30.1-1
sudo apt update && sudo apt install --only-upgrade webkit2gtk dpkg --compare-versions "$(dpkg-query -W -f='${Version}' webkit2gtk)" ge "2.30.1-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 12 · wpewebkit · FIXED · 2.30.0-1
sudo apt update && sudo apt install --only-upgrade wpewebkit dpkg --compare-versions "$(dpkg-query -W -f='${Version}' wpewebkit)" ge "2.30.0-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · wpewebkit · FIXED · 2.30.0-1
sudo apt update && sudo apt install --only-upgrade wpewebkit dpkg --compare-versions "$(dpkg-query -W -f='${Version}' wpewebkit)" ge "2.30.0-1" && echo PATCHED || echo STILL-VULNERABLE
RHEL 7 Extended Lifecycle Support · webkitgtk4 · FIXED · webkitgtk4-2.48.3-2.el7_9
sudo dnf upgrade --advisory=RHSA-2025:10364 rpm -q webkitgtk4
RHEL 8 · webkit2gtk3 · FIXED · webkit2gtk3-2.30.4-1.el8
sudo dnf upgrade --advisory=RHSA-2021:1586 rpm -q webkit2gtk3
RHEL 6 · webkitgtk · NO FIX YET
RHEL 7 · webkitgtk3 · NO FIX YET
RHEL 9 · webkit2gtk3 · NOT AFFECTED
Alpine 3.20 · webkit2gtk · FIXED · webkit2gtk-2.30.0-r0
apk add --upgrade webkit2gtk apk info -v webkit2gtk
Amazon Linux 2 · see advisory · FIXED · ALAS2-2023-2088 · source
sudo yum update --advisory=ALAS2-2023-2088
Verify at the official source NVD · CVE Program · CISA KEV catalog · 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-2021-30661?

safari: upgrade to 14.1; ipados: upgrade to 14.5; iphone os: upgrade to 12.5.3, 14.5. Exact commands for each OS are on this page.

Is CVE-2021-30661 being exploited?

Yes. CVE-2021-30661 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

What does CVE-2021-30661 affect?

CVE-2021-30661 affects safari, ipados, iphone os. Severity is high (CVSS 8.8). A use after free issue was addressed with improved memory management. This issue is fixed in Safari 14.1, iOS 12.5.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5, macOS Big Sur 11.3. Processing maliciously crafted web content may lead

How urgent is CVE-2021-30661?

Priority 79/100. High severity; EPSS top 9%: very likely to be exploited; Exploited in the wild (CISA KEV)

Software pages

iOS vulnerabilities · macOS vulnerabilities · Safari vulnerabilities · WebKit vulnerabilities · Apple Safari and WebKit vulnerabilities · iPadOS vulnerabilities

Related CVEs

References

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