dbcve.org
SafariWeb browser · Apple

CVE-2021-30809

HIGH · 8.8 CVSS v3.1 Published 2021-10-28
Fix available
A fix is available. Upgrade to 8.0 / 12.0.1 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 use after free issue was addressed with improved memory management. This issue is fixed in Safari 15, tvOS 15, watchOS 8, iOS 15 and iPadOS 15. 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 use-after-free vulnerability in WebKit allows arbitrary code execution when processing maliciously crafted web content. The vulnerability affects Safari 15, iOS 15, iPadOS 15, tvOS 15, and watchOS 8. Attackers can exploit this by tricking users into visiting specially crafted webpages.

MitigationUpdate all affected Apple devices (iPhones, iPads, Apple Watch, Apple TV, and Macs running Safari 15) to the latest patched versions via Software Update. For applications embedding WKWebView, rebuild with the updated iOS/macOS SDK containing the WebKit fix.

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
IpadosOperating system
Affected:< 15.0
Iphone OsOperating system
Affected:< 15.0
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
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 > About Safari to view the version number
    Affected if Version is earlier than 15.0 on macOS systems running Safari 15, or earlier than 12.0.1 on macOS Monterey systems
  2. Check iOS version on iPhone or iPad
    Go to Settings > General > About to view the iOS version
    Affected if Version is earlier than 15.0 on iPhone or iPad
  3. Check iPadOS version on iPad
    Go to Settings > General > About to view the iPadOS version
    Affected if Version is earlier than 15.0 on iPad
  4. Check macOS version
    Go to Apple menu > About This Mac to view the macOS version
    Affected if macOS version is earlier than 12.0.1 (Monterey) when using Safari
  5. Check tvOS version on Apple TV
    Go to Settings > General > About TV to view the tvOS version
    Affected if Version is earlier than 15.0 on Apple TV
  6. Check watchOS version on Apple Watch
    Open the Watch app on iPhone, go to General > About to view watchOS version
    Affected if Version is earlier than 8.0 on Apple Watch

A user is affected if they are running any Safari version earlier than 15.0, or any iOS/iPadOS/tvOS/watchOS version earlier than 15.0/8.0/12.0.1 respectively, and they browse untrusted web content or use apps that embed WKWebView.

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 / 15.0 or later
Fixed in 8.012.0.115.0
Interim mitigation

Update all affected Apple devices (iPhones, iPads, Apple Watch, Apple TV, and Macs running Safari 15) to the latest patched versions via Software Update. For applications embedding WKWebView, rebuild with the updated iOS/macOS SDK containing the WebKit fix.

Recommended fix High confidence

iOS 15+, iPadOS 15+, macOS 12.0.1+, Safari 15, tvOS 15, watchOS 8

  1. Upgrade iOS devices to iOS 15 or later
  2. Upgrade iPadOS devices to iPadOS 15 or later
  3. Upgrade macOS to version 12.0.1 (Monterey) or later
  4. Upgrade Safari to version 15 or later
  5. Upgrade tvOS devices to tvOS 15 or later
  6. Upgrade Apple Watch devices to watchOS 8 or later

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
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

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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-2021-30809 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