dbcve.org
SafariWeb browser · Apple

CVE-2021-1844

HIGH · 8.8 CVSS v3.1 Published 2021-04-02
Fix available
A fix is available. Upgrade to 7.3.2 / 11.2.3 or later.
See remediation →
95/100
Remediation priority · Urgent
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 memory corruption issue was addressed with improved validation. This issue is fixed in iOS 14.4.1 and iPadOS 14.4.1, Safari 14.0.3 (v. 14610.4.3.1.7 and 15610.4.3.1.7), watchOS 7.3.2, macOS Big Sur 11.2.3. 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

Memory corruption vulnerability in WebKit (Safari's rendering engine) that allows arbitrary code execution when processing maliciously crafted web content. The vulnerability was addressed with improved memory validation in affected Apple operating systems.

MitigationApply available security updates: iOS 14.4.1, iPadOS 14.4.1, Safari 14.0.3, watchOS 7.3.2, or macOS Big Sur 11.2.3 to vulnerable devices.

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
SafariWeb browser
Affected:< 14.0.3
Debian LinuxOperating system
Affected:= 10.0
FedoraOperating system
Affected:= 33
IpadosOperating system
Affected:< 14.4.1
Iphone OsOperating system
Affected:< 14.4.1
macOSOperating system
Affected:< 11.2.3
TvosOperating system
Affected:< 14.5
WatchosOperating system
Affected:< 7.3.2

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. Identify your Apple device type and operating system
    Determine whether the device is running macOS, iOS, iPadOS, watchOS, or tvOS. Check System Preferences > About or Settings > General > About on iOS devices.
    Affected if Device runs any of the affected Apple operating systems listed in the CVE
  2. Check macOS version on Mac computers
    Run `sw_vers` in Terminal or open System Preferences > About to view the macOS version number.
    Affected if macOS version is below 11.2.3 (Big Sur)
  3. Check Safari version on macOS
    Open Safari > About Safari or run `defaults read /Applications/Safari.app/Contents/Info CFBundleShortVersionString` in Terminal.
    Affected if Safari version is below 14.0.3
  4. Check iOS or iPadOS version on iPhone or iPad
    Open Settings > General > About to view the iOS/iPadOS version number.
    Affected if iOS version is below 14.4.1 or iPadOS version is below 14.4.1
  5. Check watchOS version on Apple Watch
    Open the Watch app on iPhone, go to General > About, or check Settings > About on the Apple Watch itself.
    Affected if watchOS version is below 7.3.2
  6. Check tvOS version on Apple TV
    Open Settings > General > About on Apple TV to view the tvOS version.
    Affected if tvOS version is below 14.5

You are affected if your Safari, iOS, iPadOS, macOS, watchOS, or tvOS version falls below the specific patched version numbers listed, and you use the browser to process web content.

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 7.3.2 / 11.2.3 / 14.0.3 or later
Fixed in 7.3.211.2.314.0.3
Interim mitigation

Apply available security updates: iOS 14.4.1, iPadOS 14.4.1, Safari 14.0.3, watchOS 7.3.2, or macOS Big Sur 11.2.3 to vulnerable devices.

Recommended fix High confidence

Apple products: iOS 14.4.1, iPadOS 14.4.1, macOS 11.2.3, watchOS 7.3.2, tvOS 14.5, Safari 14.0.3

  1. For iPhone OS: Upgrade to iOS 14.4.1 or later
  2. For iPadOS: Upgrade to iPadOS 14.4.1 or later
  3. For macOS: Upgrade to macOS Big Sur 11.2.3 or later
  4. For watchOS: Upgrade to watchOS 7.3.2 or later
  5. For tvOS: Upgrade to tvOS 14.5 or later
  6. For Safari: Upgrade to Safari 14.0.3 or later
  7. For Linux distributions (Debian 10.0, Fedora 33): Apply distribution-specific security updates for webkit2gtk or webkitgtk packages when available, as this vulnerability affects the WebKit rendering engine used by browsers on those platforms
Caveat Standard Apple OS updates may include feature changes; ensure compatibility testing for critical workflows before mass deployment

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

Fix this in Safari Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,780
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,848.

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-2021-1844 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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