dbcve.org
SafariWeb browser · Apple

CVE-2020-9948

HIGH · 8.8 CVSS v3.1 Published 2020-10-16
Fix available
A fix is available. Upgrade to 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 type confusion issue was addressed with improved memory handling. This issue is fixed in Safari 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 type confusion vulnerability in Safari's rendering engine allows remote attackers to execute arbitrary code via maliciously crafted web content. The issue stems from improper memory handling during type conversion operations, which can be triggered when processing specially crafted HTML or JavaScript.

MitigationUpdate Safari to version 14.0 or later on all affected endpoints to remediate this vulnerability.

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
Debian LinuxOperating system
Affected:= 10.0
Webkitgtk\+Web browser
Affected:<= 2.30.3

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/iOS
    Open Safari > About Safari or run 'defaults read /Applications/Safari.app/Contents/Info CFBundleShortVersionString' in Terminal
    Affected if Version is less than 14.0 (e.g., 13.1.x, 13.0.x, etc.)
  2. Check WebKitGTK+ version on Linux systems
    Run 'dpkg -l | grep webkit' or 'rpm -qa | grep webkit' depending on package manager, or check the shared library version with 'ldd' on applications linked against webkit
    Affected if WebKitGTK+ version is 2.30.3 or lower
  3. Verify Safari is the default browser
    Check system preferences or run 'defaults read com.apple.LaunchServices.plist' to see default browser handler
    Affected if Safari is set as default and runs web content
  4. Identify applications using WebKit on Debian 10
    Run 'dpkg -s libwebkit2gtk-4.0-37' or check installed packages containing webkit2gtk
    Affected if libwebkit2gtk-4.0-37 or webkit2gtk package is installed with version <= 2.30.3

You are affected if Safari version is below 14.0 on your Apple devices, or if WebKitGTK+ version is 2.30.3 or lower on Linux/Debian systems that 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.

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

Update Safari to version 14.0 or later on all affected endpoints to remediate this vulnerability.

Fix this in Safari Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,424.

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-2020-9948 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