dbcve.org
SafariWeb browser · Apple

CVE-2021-30744

MEDIUM · 6.1 CVSS v3.1 Published 2021-09-08
Fix available
A fix is available. Upgrade to 7.5 / 11.4 or later.
See remediation →
68/100
Remediation priority · Elevated
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
Description: A cross-origin issue with iframe elements was addressed with improved tracking of security origins. This issue is fixed in tvOS 14.6, iOS 14.6 and iPadOS 14.6, Safari 14.1.1, macOS Big Sur 11.4, watchOS 7.5. Processing maliciously crafted web content may lead to universal cross site scripting.

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 cross-origin issue in Safari and Apple browsers allows malicious web content to bypass iframe origin tracking, enabling universal cross-site scripting (UXSS) where an attacker can inject scripts into any website from a malicious page.

MitigationApply the vendor patches: Safari 14.1.1, iOS/iPadOS 14.6, macOS Big Sur 11.4, tvOS 14.6, or watchOS 7.5. This is a browser/OS update requiring patch deployment across affected endpoints.

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:< 14.1.1
IpadosOperating system
Affected:< 14.6
Iphone OsOperating system
Affected:< 14.6
macOSOperating system
Affected:>= 11.0.1, < 11.4
TvosOperating system
Affected:< 14.6
WatchosOperating system
Affected:< 7.5

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
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

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 Safari version on macOS
    Open Safari, then go to Safari > About Safari. Note the version number displayed.
    Affected if Version is earlier than 14.1.1
  2. Check iOS or iPadOS version
    Open Settings > General > About on the device. Note the version number.
    Affected if Version is earlier than 14.6
  3. Check macOS Big Sur version
    Click the Apple menu > About This Mac. Note the macOS version number.
    Affected if macOS version is 11.0.1, 11.0.2, 11.0.3, 11.1, 11.2, or 11.3 (any version >= 11.0.1 but < 11.4)
  4. Check tvOS version
    Open Settings > General > About TV on the Apple TV device. Note the version number.
    Affected if Version is earlier than 14.6
  5. Check watchOS version
    Open Settings > General > About on Apple Watch via the Watch app on iPhone, or directly on the watch. Note the version number.
    Affected if Version is earlier than 7.5

If the installed Safari browser version is below 14.1.1, or the iOS/iPadOS/tvOS/watchOS version is below 14.6, or macOS Big Sur is between 11.0.1 and 11.3.x, the browser is vulnerable to this cross-origin bypass.

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 7.5 / 11.4 / 14.1.1 or later
Fixed in 7.511.414.1.1
Interim mitigation

Apply the vendor patches: Safari 14.1.1, iOS/iPadOS 14.6, macOS Big Sur 11.4, tvOS 14.6, or watchOS 7.5. This is a browser/OS update requiring patch deployment across affected endpoints.

Recommended fix High confidence

Safari 14.1.1, iOS 14.6, iPadOS 14.6, macOS Big Sur 11.4, tvOS 14.6, watchOS 7.5 (or later)

  1. Identify the affected Apple product (Safari, iOS, iPadOS, macOS, tvOS, or watchOS)
  2. Check current version of the product
  3. For iOS/iPadOS: Go to Settings > General > Software Update and install the update (iOS 14.6+, iPadOS 14.6+)
  4. For macOS: Use System Preferences > Software Update or download macOS Big Sur 11.4 from apple.com
  5. For Safari: Update via macOS Software Update (Safari 14.1.1 included in macOS 11.4)
  6. For tvOS: Go to Settings > General > Software Update and install tvOS 14.6+
  7. For watchOS: Go to Settings > General > Software Update on iPhone paired with Apple Watch and install watchOS 7.5+
  8. After updating, verify the version matches or exceeds the fixed release
Caveat Standard minor OS/browser update - minimal risk; standard backup recommended before updating

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

Fix this in Safari Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.

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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-2021-30744 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