dbcve.org
FedoraOperating system · Fedoraproject

CVE-2020-13753

CRITICAL · 10.0 CVSS v3.1 Published 2020-07-14
Fix available
A fix is available. Upgrade to 2.28.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

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
The bubblewrap sandbox of WebKitGTK and WPE WebKit, prior to 2.28.3, failed to properly block access to CLONE_NEWUSER and the TIOCSTI ioctl. CLONE_NEWUSER could potentially be used to confuse xdg-desktop-portal, which allows access outside the sandbox. TIOCSTI can be used to directly execute commands outside the sandbox by writing to the controlling terminal's input buffer, similar to CVE-2017-5226.

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

WebKitGTK and WPE WebKit bubblewrap sandbox prior to version 2.28.3 fails to properly block CLONE_NEWUSER and the TIOCSTI ioctl. CLONE_NEWUSER can be exploited to confuse xdg-desktop-portal into granting unauthorized access outside the sandbox, while TIOCSTI allows writing directly to the controlling terminal's input buffer to execute arbitrary commands outside the sandbox.

MitigationUpgrade WebKitGTK or WPE WebKit to version 2.28.3 or later to obtain the patched bubblewrap sandbox configuration that properly blocks CLONE_NEWUSER and TIOCSTI.

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
FedoraOperating system
Affected:= 31
Debian LinuxOperating system
Affected:= 10.0
Ubuntu LinuxOperating system
Affected:= 18.04= 19.10= 20.04
WebkitgtkWeb browser
Affected:< 2.28.3
Wpe WebkitWeb browser
Affected:< 2.28.3
LeapOperating system
Affected:= 15.1

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
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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 WebKitGTK or WPE WebKit installation
    Check if webkitgtk or wpewebkit packages are installed using your system package manager (e.g., rpm -qa | grep -i webkit, dpkg -l | grep -i webkit, or zypper se webkit)
    Affected if Either webkitgtk or wpewebkit package is installed on the system
  2. Check installed WebKit version
    Run 'rpm -q --queryformat "%{VERSION}\n" webkitgtk4' or 'dpkg -l libwebkit2gtk-4.0-37' or the equivalent for your package manager to get the version number, then compare to the vulnerable range (versions below 2.28.3)
    Affected if Installed version is less than 2.28.3
  3. Verify bubblewrap sandbox is in use
    Check if the webkit process uses bubblewrap by inspecting running processes or configuration: look for 'bubblewrap' or 'bwrap' in process listings (ps aux | grep -i bwrap) or check WebKit configuration files that reference sandboxing
    Affected if Bubblewrap sandbox is actively being used by WebKit applications
  4. Inspect bubblewrap sandbox configuration
    Examine the bubblewrap wrapper script or configuration shipped with WebKitGTK/WPE for missing CLONE_NEWUSER and TIOCSTI restrictions - check for the presence of '--unshare-user' or '--new-session' flags in sandbox launch configurations, or inspect /usr/libexec/webkit2gtk-4.0/resources/helper or similar sandbox helper paths
    Affected if The bubblewrap configuration lacks proper blocking of CLONE_NEWUSER namespace and TIOCSTI ioctl (sandbox helper allows user namespace or permits TIOCSTI)

A user is affected if WebKitGTK or WPE WebKit version 2.28.3 or newer is not installed AND the bubblewrap sandbox is being used to isolate web content, allowing potential escape via CLONE_NEWUSER or TIOCSTI ioctl exploitation.

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 2.28.3 or later
Fixed in 2.28.3
Vendor patch trac.webkit.org →
Interim mitigation

Upgrade WebKitGTK or WPE WebKit to version 2.28.3 or later to obtain the patched bubblewrap sandbox configuration that properly blocks CLONE_NEWUSER and TIOCSTI.

Recommended fix High confidence

WebKitGTK/WPE WebKit 2.28.3

  1. For Fedora: Run 'sudo dnf update webkit2gtk' or 'sudo dnf update' to apply all updates, including webkit2gtk to version 2.28.3 or later
  2. For Debian/Ubuntu: Run 'sudo apt update && sudo apt upgrade' or 'sudo apt install libwebkit2gtk-4.0-37' to get version 2.28.3 or later
  3. For openSUSE Leap: Run 'sudo zypper update' or 'sudo zypper in webkit2gtk3' to obtain the fixed version
  4. Verify the installed version using: 'dpkg -l | grep webkit' (Debian/Ubuntu) or 'rpm -qa | grep webkit' (Fedora/openSUSE)
  5. Ensure the version is 2.28.3 or higher before considering the vulnerability mitigated
Caveat Upgrading WebKit libraries may require restarting applications that depend on the old version; some applications may have minor API behavior changes

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

Fix this in Fedora Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,340
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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-2020-13753 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