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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 25 May 2022.
FedoraOperating system · Fedoraproject

CVE-2021-1789

HIGH · 8.8 CVSS v3.1 Published 2021-04-02
Fix available
A fix is available. Upgrade to 2.30.6 / 7.3 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A type confusion issue was addressed with improved state handling. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, tvOS 14.4, watchOS 7.3, iOS 14.4 and iPadOS 14.4, Safari 14.0.3. Processing maliciously crafted web content may lead to arbitrary code execution.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A type confusion vulnerability in WebKit (Safari's browser engine) allows arbitrary code execution when processing maliciously crafted web content. The vulnerability stems from improper state handling during JavaScript object type processing, which can be exploited to achieve code execution outside the sandbox.

MitigationUpdate affected Apple devices to iOS 14.4/iPadOS 14.4, watchOS 7.3, tvOS 14.4, macOS Big Sur 11.2/Security Update 2021-001, or Safari 14.0.3. For enterprise environments, deploy the appropriate Apple security updates via MDM or patch management tools.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FedoraOperating system
Affected:= 32= 33
IpadosOperating system
Affected:< 14.4
Iphone OsOperating system
Affected:< 14.4
Mac Os XOperating system
Affected:>= 10.14, < 10.14.6>= 10.15, < 10.15.7= 10.14.6= 10.15.7
macOSOperating system
Affected:>= 11.0, < 11.2
TvosOperating system
Affected:< 14.4
WatchosOperating system
Affected:< 7.3
WebkitgtkWeb browser
Affected:< 2.30.6

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check macOS version
    Run 'sw_vers -productVersion' in Terminal to get the installed macOS version
    Affected if Version is 10.14.6, 10.14.5 or earlier from 10.14.x series; or 10.15.7, 10.15.6 or earlier from 10.15.x series; or 11.0, 11.1 (11.2 is fixed)
  2. Check iOS or iPadOS version
    Go to Settings > General > About on the device to view the iOS/iPadOS version number
    Affected if Version is earlier than 14.4 (for example, 14.3, 14.2, etc.)
  3. Check tvOS version
    Go to Settings > General > About > Version on Apple TV to view the tvOS version
    Affected if Version is earlier than 14.4 (for example, 14.3, 14.2, etc.)
  4. Check watchOS version
    Open the Watch app on iPhone, go to My Watch > General > About to view watchOS version
    Affected if Version is earlier than 7.3 (for example, 7.2, 7.1, etc.)
  5. Check WebKitGTK version
    Run 'dpkg -l | grep webkit' or 'rpm -qa | grep webkit' to list installed WebKitGTK packages and their versions
    Affected if WebKitGTK version is earlier than 2.30.6 (for example, 2.30.5, 2.30.4, etc.)

You are affected if any Apple device (iPhone, iPad, Mac, Apple TV, Apple Watch) or WebKitGTK installation runs a version lower than the fixed releases: macOS 10.14.6+, 10.15.7+, 11.2+; iOS/iPadOS 14.4+; tvOS 14.4+; watchOS 7.3+; WebKitGTK 2.30.6+

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.30.6 / 7.3 / 10.14.6 or later
Fixed in 2.30.67.310.14.6
Interim mitigation

Update affected Apple devices to iOS 14.4/iPadOS 14.4, watchOS 7.3, tvOS 14.4, macOS Big Sur 11.2/Security Update 2021-001, or Safari 14.0.3. For enterprise environments, deploy the appropriate Apple security updates via MDM or patch management tools.

Recommended fix High confidence

Apple: iOS 14.4+/iPadOS 14.4+/watchOS 7.3+/tvOS 14.4+/macOS 11.2+; WebKitGTK: 2.30.6+; Fedora: 34+

  1. For Apple devices (iOS, iPadOS, watchOS, tvOS, macOS): Upgrade to iOS 14.4 or later, iPadOS 14.4 or later, watchOS 7.3 or later, tvOS 14.4 or later, or macOS 11.2 or later respectively
  2. For older macOS versions (10.14 Mojave and 10.15 Catalina): Install Security Update 2021-001
  3. For Safari: Update to Safari 14.0.3 or later via Software Update
  4. For WebKitGTK-based browsers (Linux): Upgrade WebKitGTK to version 2.30.6 or later
  5. For Fedora: Upgrade to Fedora 34 or later (Fedora 32 and 33 are end-of-life)
Caveat None expected - this is a security update with no known compatibility breaks

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fedora Exploited in the wild — priority engagement
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-1789 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data