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SafariWeb browser · Apple

CVE-2020-9950

HIGH · 8.8 CVSS v3.1 Published 2020-12-08
Fix available
A fix is available. Upgrade to 7.0 / 14.0 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 watchOS 7.0, tvOS 14.0, Safari 14.0, iOS 14.0 and iPadOS 14.0. 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 remote attackers to execute arbitrary code via maliciously crafted web content. The vulnerability stems from improper memory management where memory is accessed after being freed, potentially allowing an attacker to control execution flow.

MitigationApply vendor patches by updating affected devices to iOS 14.0+, iPadOS 14.0+, tvOS 14.0+, watchOS 7.0+, or Safari 14.0+ as appropriate. Implement network-level content filtering as an interim control.

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
IpadosOperating system
Affected:< 14.0
Iphone OsOperating system
Affected:< 14.0
TvosOperating system
Affected:< 14.0
WatchosOperating system
Affected:< 7.0

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. Identify your Apple device and browser products
    Determine which Apple products are installed: iPhone, iPad, Apple TV, Apple Watch, or Safari on macOS. Note that this vulnerability affects WebKit which is used by Safari across all platforms and by the default browsers on iOS, iPadOS, tvOS, and watchOS.
    Affected if Any Apple device running the listed products is potentially affected
  2. Check iOS version on iPhone or iPad
    On iPhone or iPad, go to Settings > General > About and note the version number displayed next to 'Version'. Compare this version to the affected range (all versions before 14.0).
    Affected if The installed iOS version is lower than 14.0
  3. Check iPadOS version on iPad
    On iPad, go to Settings > General > About and note the version number displayed next to 'Version'. Compare this version to the affected range (all versions before 14.0).
    Affected if The installed iPadOS version is lower than 14.0
  4. Check tvOS version on Apple TV
    On Apple TV, go to Settings > General > About > Version and note the displayed version number. Compare this version to the affected range (all versions before 14.0).
    Affected if The installed tvOS version is lower than 14.0
  5. Check watchOS version on Apple Watch
    On Apple Watch, open the Watch app on your paired iPhone, go to General > About, and note the watchOS version. Alternatively, on Apple Watch go to Settings > General > About. Compare this version to the affected range (all versions before 7.0).
    Affected if The installed watchOS version is lower than 7.0
  6. Check Safari version
    Open Safari and go to Safari > About Safari (on macOS) or open Settings > Safari > About (on iOS/iPadOS). Note the version number. Compare this version to the affected range (all versions before 14.0).
    Affected if The installed Safari version is lower than 14.0

If any Apple device or Safari installation has a version lower than 14.0 (or lower than 7.0 for watchOS), the environment is affected by this vulnerability.

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.

From vendor data
Upgrade available Upgrade to 7.0 / 14.0 or later
Fixed in 7.014.0
Interim mitigation

Apply vendor patches by updating affected devices to iOS 14.0+, iPadOS 14.0+, tvOS 14.0+, watchOS 7.0+, or Safari 14.0+ as appropriate. Implement network-level content filtering as an interim control.

Fix this in Safari Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,800
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,480.

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-2020-9950 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