CVE
CVE-2021-30663
Apple Multiple Products WebKit Integer Overflow Vulnerability
An integer overflow was addressed with improved input validation. This issue is fixed in iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS 12.5.3, Safari 14.1.1, macOS Big Sur 11.3.1. Processing maliciously crafted web content may lead to arbitrary code execution.
HIGH · CVSS 8.8
⚠ CISA KEV
EPSS 0.00173
Act now
- Listed on CISA KEV (known exploited in the wild)
- SSVC exploitation status: active
- Public exploit or PoC is available
- CVSS base score ≥ 7.0
Sigma rules8
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2021-30663, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
⬢
Required Remediation
Apply updates per vendor instructions.
◆
ATT&CK techniques
2Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.
▤ Build a SIEM detection for these techniques▤
CAPEC attack patterns
1Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.
⬡
Weakness Classification
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Affected Products & Versions
6apple safari< 14.1.1
apple ipados>= 14.0 and < 14.5.1
apple iphone os< 12.5.3
apple iphone os>= 14.0 and < 14.5.1
apple macos>= 11.0 and < 11.3.1
apple tvos< 14.6
▤
Affected Packages
14Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Ubuntu:18.04:LTS
webkit2gtk
fixed in 2.32.3-0ubuntu0.18.04.1
Ubuntu:20.04:LTS
qtwebkit-opensource-src
Ubuntu:20.04:LTS
webkit2gtk
fixed in 2.32.3-0ubuntu0.20.04.1
Ubuntu:20.04:LTS
wpewebkit
Ubuntu:22.04:LTS
qtwebkit-opensource-src
Ubuntu:22.04:LTS
wpewebkit
Ubuntu:24.04:LTS
qtwebkit-opensource-src
Ubuntu:Pro:16.04:LTS
qtwebkit-opensource-src
Ubuntu:Pro:16.04:LTS
qtwebkit-source
Ubuntu:Pro:16.04:LTS
webkit2gtk
Ubuntu:Pro:16.04:LTS
webkitgtk
Ubuntu:Pro:18.04:LTS
qtwebkit-opensource-src
Ubuntu:Pro:18.04:LTS
qtwebkit-source
Ubuntu:Pro:18.04:LTS
webkitgtk
⚠
Public Exploits & PoCs
4These PoC and exploit links come from public sources and are not verified to be safe or functional. Review the code before running anything, and treat unverified entries as untrusted.
📦
Fixed versions by distribution
80The package version that resolves this CVE on each Linux distribution, from the vendor’s published security data. fixed in shows a patched version exists; open means the package is listed as affected with no fix yet.
alpine v3.19webkit2gtk fixed in 2.32.3-r0
alpine v3.20webkit2gtk fixed in 2.32.3-r0
oracle allLibRaw fixed in 0:0.19.5-3.el8
oracle allLibRaw-devel open
oracle allaccountsservice fixed in 0:0.6.55-2.el8
oracle allaccountsservice-devel open
oracle allaccountsservice-libs fixed in 0:0.6.55-2.el8
oracle allgdm fixed in 1:40.0-15.el8
oracle allgnome-autoar fixed in 0:0.2.3-2.el8
oracle allgnome-calculator fixed in 0:3.28.2-2.el8
oracle allgnome-classic-session fixed in 0:3.32.1-20.el8
oracle allgnome-control-center open
oracle allgnome-control-center-filesystem open
oracle allgnome-online-accounts open
oracle allgnome-online-accounts-devel open
oracle allgnome-session fixed in 0:3.28.1-13.0.1.el8
oracle allgnome-session-kiosk-session open
oracle allgnome-session-wayland-session open
oracle allgnome-session-xsession fixed in 0:3.28.1-13.0.1.el8
oracle allgnome-settings-daemon open
oracle allgnome-shell fixed in 0:3.32.2-40.el8
oracle allgnome-shell-extension-apps-menu open
oracle allgnome-shell-extension-auto-move-windows open
oracle allgnome-shell-extension-common fixed in 0:3.32.1-20.el8
oracle allgnome-shell-extension-dash-to-dock open
oracle allgnome-shell-extension-desktop-icons fixed in 0:3.32.1-20.el8
oracle allgnome-shell-extension-disable-screenshield open
oracle allgnome-shell-extension-drive-menu open
oracle allgnome-shell-extension-gesture-inhibitor open
oracle allgnome-shell-extension-horizontal-workspaces fixed in 0:3.32.1-20.el8
oracle allgnome-shell-extension-launch-new-instance open
oracle allgnome-shell-extension-native-window-placement fixed in 0:3.32.1-20.el8
oracle allgnome-shell-extension-no-hot-corner fixed in 0:3.32.1-20.el8
oracle allgnome-shell-extension-panel-favorites open
oracle allgnome-shell-extension-places-menu open
oracle allgnome-shell-extension-screenshot-window-sizer fixed in 0:3.32.1-20.el8
oracle allgnome-shell-extension-systemMonitor open
oracle allgnome-shell-extension-top-icons open
oracle allgnome-shell-extension-updates-dialog open
oracle allgnome-shell-extension-user-theme open
oracle allgnome-shell-extension-window-grouper fixed in 0:3.32.1-20.el8
oracle allgnome-shell-extension-window-list open
oracle allgnome-shell-extension-windowsNavigator fixed in 0:3.32.1-20.el8
oracle allgnome-shell-extension-workspace-indicator fixed in 0:3.32.1-20.el8
oracle allgnome-software fixed in 0:3.36.1-10.el8
oracle allgnome-software-devel fixed in 0:3.36.1-10.el8
oracle allgsettings-desktop-schemas fixed in 0:3.32.0-6.el8
oracle allgsettings-desktop-schemas-devel fixed in 0:3.32.0-6.el8
oracle allgtk-update-icon-cache fixed in 0:3.22.30-8.el8
oracle allgtk3 open
oracle allgtk3-devel open
oracle allgtk3-immodule-xim open
oracle allmutter fixed in 0:3.32.2-60.el8
oracle allmutter-devel open
oracle allvino open
oracle allwebkit2gtk3 open
oracle allwebkit2gtk3-devel fixed in 0:2.32.3-2.el8
oracle allwebkit2gtk3-jsc fixed in 0:2.32.3-2.el8
oracle allwebkit2gtk3-jsc-devel open
rhel 8LibRaw open
rhel 8LibRaw-devel open
rhel 8gnome-autoar open
rhel 8webkit2gtk3 open
rhel 8webkit2gtk3-devel fixed in 0:2.32.3-2.el8
rhel 8webkit2gtk3-jsc open
rhel 8webkit2gtk3-jsc-devel fixed in 0:2.32.3-2.el8
suse sle15WebKitGTK-4.0-lang fixed in 0:2.48.1-150600.12.36.5
suse sle15WebKitGTK-4.1-lang fixed in 0:2.48.1-150600.12.36.5
suse sle15WebKitGTK-6.0-lang fixed in 0:2.48.1-150600.12.36.5
suse sle15libjavascriptcoregtk-4_0-18 fixed in 0:2.32.3-3.77.3
suse sle15libjavascriptcoregtk-4_1-0 fixed in 0:2.38.6-150400.4.39.1
suse sle15libjavascriptcoregtk-5_0-0 fixed in 0:2.36.0-150400.2.12
suse sle15libjavascriptcoregtk-6_0-1 fixed in 0:2.48.1-150600.12.36.5
suse sle15libsoup-2_4-1 fixed in 0:2.62.2-17.8.1
suse sle15libsoup-devel fixed in 0:2.62.2-17.8.1
suse sle15libsoup-lang fixed in 0:2.62.2-17.8.1
suse sle15libwebkit2gtk-4_0-37 fixed in 0:2.32.3-3.77.3
suse sle15libwebkit2gtk-4_1-0 fixed in 0:2.48.1-150600.12.36.5
suse sle15libwebkit2gtk-5_0-0 fixed in 0:2.36.0-150400.2.12
suse sle15libwebkit2gtk3-lang fixed in 0:2.32.3-3.77.3
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Sigma Hunt Rules
8Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighSuspicious Microsoft Office Child Process - MacOS
producthighRemote Access Tool - Renamed MeshAgent Execution - MacOS
producthighBinary Padding - MacOS
productmediumSuspicious Execution via macOS Script Editor
productmediumSystem Information Discovery Via Sysctl - MacOS
productmediumNew File Exclusion Added To Time Machine Via Tmutil - MacOS
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Scoring & Timeline
8.8
HIGH · CVSS v3.1 · [email protected]
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
SSVC triage · cisa-vulnrichment
Exploitation
active
Automatable
no
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑
Vendor Advisories
9suse-csafSUSE-SU-2021:2762-1
suse-csafopenSUSE-SU-2021:1101-1
suse-csafopenSUSE-SU-2021:2598-1
🔗
References & Sources
6Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30663Third Party AdvisoryUS Government Resource