dbcve.org
SafariWeb browser · Apple

CVE-2021-30749

HIGH · 8.8 CVSS v3.1 Published 2021-09-08
Fix available
A fix is available. Upgrade to 7.5 / 11.4 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
Multiple memory corruption issues were addressed with improved memory handling. 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 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

CVE-2021-30749 is a memory corruption vulnerability in WebKit (the browser engine used by Safari and UIKit-based apps) affecting multiple Apple platforms. Processing maliciously crafted web content triggers memory corruption that can be exploited to achieve arbitrary code execution. This is a client-side code execution vulnerability exploitable through web browsing.

MitigationApply Apple's security updates: upgrade to iOS/iPadOS 14.6+, macOS Big Sur 11.4+, tvOS 14.6+, watchOS 7.5+, and Safari 14.1.1+. Disable JavaScript or restrict untrusted web browsing if updates cannot be applied immediately.

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, < 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
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 Safari version on macOS
    Open Safari, go to Safari menu > About Safari. Compare the version number to the affected range.
    Affected if Safari version is earlier than 14.1.1
  2. Check iOS version on iPhone
    Open Settings > General > About. Note the version number shown next to 'Software Version'.
    Affected if iOS version is earlier than 14.6
  3. Check iPadOS version on iPad
    Open Settings > General > About. Note the version number shown next to 'Software Version'.
    Affected if iPadOS version is earlier than 14.6
  4. Check macOS version
    Click the Apple menu > About This Mac. The version number is displayed under the macOS name.
    Affected if macOS version is 11.0 through 11.3.x (Big Sur 11.0 to 11.3)
  5. Check tvOS version
    Open Settings > General > About TV. Note the version number.
    Affected if tvOS version is earlier than 14.6
  6. Check watchOS version
    On paired iPhone, open Watch app > My Watch > General > About. Note the watchOS version.
    Affected if watchOS version is earlier than 7.5

Your environment is affected if any device or browser listed above is running a version lower than the minimum fixed version for that product.

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 Apple's security updates: upgrade to iOS/iPadOS 14.6+, macOS Big Sur 11.4+, tvOS 14.6+, watchOS 7.5+, and Safari 14.1.1+. Disable JavaScript or restrict untrusted web browsing if updates cannot be applied immediately.

Recommended fix High confidence

iOS 14.6, iPadOS 14.6, macOS Big Sur 11.4, tvOS 14.6, watchOS 7.5, Safari 14.1.1

  1. Identify the affected Apple device type (iPhone, iPad, Mac, Apple Watch, Apple TV, or Safari browser)
  2. Determine the current installed version of the operating system or Safari
  3. For iPhone: upgrade to iOS 14.6 or later
  4. For iPad: upgrade to iPadOS 14.6 or later
  5. For Mac: upgrade to macOS Big Sur 11.4 or later
  6. For Apple TV: upgrade to tvOS 14.6 or later
  7. For Apple Watch: upgrade to watchOS 7.5 or later
  8. For Safari: upgrade to Safari 14.1.1 or later (bundled with macOS Big Sur 11.4)
Caveat Standard OS upgrade considerations apply - review Apple's release notes for any feature changes before upgrading

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

Fix this in Safari Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.

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-2021-30749 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