dbcve.org
SafariWeb browser · Apple

CVE-2021-30849

HIGH · 7.8 CVSS v3.1 Published 2021-10-19
Fix available
A fix is available. Upgrade to 8.0 / 12.0.1 or later.
See remediation →
81/100
Remediation priority · High
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 iOS 14.8 and iPadOS 14.8, watchOS 8, Safari 15, tvOS 15, iOS 15 and iPadOS 15, iTunes 12.12 for Windows. 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 · moderate confidence

This is a WebKit memory corruption vulnerability affecting iOS, iPadOS, watchOS, Safari, tvOS, and iTunes for Windows. Processing maliciously crafted web content triggers memory corruption issues (likely use-after-free, heap overflow, or similar), enabling arbitrary code execution with the privileges of the browser process.

MitigationApply the vendor-supplied patches: update to iOS/iPadOS 14.8 or 15, watchOS 8, Safari 15, tvOS 15, or iTunes 12.12 for Windows. For enterprises, ensure MDM-managed devices receive the updates and internal apps using WebView are tested for compatibility.

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:< 15.0
ItunesApplication
Affected:< 12.12
IpadosOperating system
Affected:< 14.8
Iphone OsOperating system
Affected:< 14.8
macOSOperating system
Affected:< 12.0.1
TvosOperating system
Affected:< 15.0
WatchosOperating system
Affected:< 8.0

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
Local
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/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 > About Safari or run 'defaults read /Applications/Safari.app/Contents/Info CFBundleShortVersionString' in Terminal
    Affected if Version is lower than 15.0 on macOS systems that browse the web
  2. Check iOS or iPadOS version
    Go to Settings > General > About on the device, or check via Apple Configurator, MDM, or device management console
    Affected if Version is lower than 14.8 on iPhones or iPads that use Safari or any app with WebView
  3. Check watchOS version
    Open the Watch app on paired iPhone > My Watch > General > About, or check via MDM
    Affected if Version is lower than 8.0 on Apple Watch devices with browser or web-based functionality
  4. Check tvOS version
    Go to Settings > General > About > Version on Apple TV, or check via MDM
    Affected if Version is lower than 15.0 on Apple TV devices using Safari app
  5. Check iTunes version on Windows
    Open iTunes > Help > About iTunes, or check via 'C:\Program Files\iTunes\iTunes.exe' properties version info
    Affected if Version is lower than 12.12 on Windows systems with iTunes installed

The environment is affected if any Apple device or software listed runs a version lower than the patched release (Safari 15+, iOS/iPadOS 14.8+, watchOS 8+, tvOS 15+, iTunes 12.12+, macOS 12.0.1+) and uses WebKit to render untrusted 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 8.0 / 12.0.1 / 12.12 or later
Fixed in 8.012.0.112.12
Interim mitigation

Apply the vendor-supplied patches: update to iOS/iPadOS 14.8 or 15, watchOS 8, Safari 15, tvOS 15, or iTunes 12.12 for Windows. For enterprises, ensure MDM-managed devices receive the updates and internal apps using WebView are tested for compatibility.

Recommended fix High confidence

iOS 14.8/iPadOS 14.8, iOS 15/iPadOS 15, macOS 12.0.1 (Monterey), Safari 15, watchOS 8, tvOS 15, iTunes 12.12 for Windows

  1. For iPhone/iPad: Go to Settings > General > Software Update and upgrade to iOS 14.8 or iOS 15
  2. For macOS: Go to System Preferences > Software Update and upgrade to macOS 12.0.1 (Monterey) or later
  3. For Safari: Update via macOS 12.0.1 or later, or download Safari 15 from Apple
  4. For Apple Watch: Open the Watch app on iPhone, go to General > Software Update and upgrade to watchOS 8
  5. For Apple TV: Go to Settings > System > Software Updates and upgrade to tvOS 15
  6. For iTunes (Windows): Download and install iTunes 12.12 for Windows from Apple
Caveat Upgrading to major OS versions (iOS 15, macOS 12, tvOS 15, watchOS 8) may introduce new features and UI changes that could affect existing workflows

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
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,224.

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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-2021-30849 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