dbcve.org
Debian LinuxOperating system · Debian

CVE-2023-39928

HIGH · 8.8 CVSS v3.1 Published 2023-10-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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 vulnerability exists in the MediaRecorder API of Webkit WebKitGTK 2.40.5. A specially crafted web page can abuse this vulnerability to cause memory corruption and potentially arbitrary code execution. A user would need to to visit a malicious webpage to trigger this vulnerability.

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

A use-after-free vulnerability in the MediaRecorder API of WebKitGTK 2.40.5 allows a specially crafted webpage to trigger memory corruption. This occurs when the MediaRecorder object is accessed after memory has been deallocated, potentially enabling arbitrary code execution in the context of the user's browser session.

MitigationUpdate WebKitGTK to the latest patched version. Until then, restrict or disable JavaScript execution on untrusted websites and consider using alternative browsers that don't rely on WebKitGTK for users accessing sensitive content.

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
Debian LinuxOperating system
Affected:= 11.0= 12.0
FedoraOperating system
Affected:= 37
WebkitgtkWeb browser
Affected:= 2.40.5

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 if WebKitGTK is installed
    On Debian/Ubuntu: dpkg -l | grep webkit. On Fedora: rpm -qa | grep webkit. On systems with pkg-config: pkg-config --modversion webkit2gtk-4.1 or webkit2gtk-4.0
    Affected if No WebKitGTK package is found in the package manager listing, indicating the software is not installed
  2. Determine the installed WebKitGTK version
    Compare the installed version number from the previous step against the affected version 2.40.5. On Debian 11/12 and Fedora 37, check if the installed version matches exactly 2.40.5
    Affected if The installed version is exactly 2.40.5, as this matches the vulnerable version specified in the CVE
  3. Identify applications using WebKitGTK
    WebKitGTK is used by GNOME Web (Epiphany) and other Linux browsers. Check if such browsers are installed: which epiphany or check desktop launcher files in /usr/share/applications for WebKit-based browsers
    Affected if An application using WebKitGTK (such as GNOME Web) is installed and used to browse web content
  4. Confirm JavaScript is enabled in the WebKit browser
    In GNOME Web: Settings > Privacy > JavaScript, or inspect the browser configuration files in ~/.config/epiphany/ or ~/.local/share/epiphany/
    Affected if JavaScript execution is enabled, which is required for the specially crafted webpage to trigger the vulnerability

You are affected if WebKitGTK version 2.40.5 is installed and a WebKitGTK-based browser with JavaScript enabled is used to access 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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update WebKitGTK to the latest patched version. Until then, restrict or disable JavaScript execution on untrusted websites and consider using alternative browsers that don't rely on WebKitGTK for users accessing sensitive content.

Recommended fix Moderate confidence

WebKitGTK 2.40.6 or later

  1. 1. Identify the current WebKitGTK version installed on the system using the package manager (e.g., dpkg -l | grep webkit, rpm -qa | grep webkit, or apt show webkitgtk-4.1)
  2. 2. Upgrade WebKitGTK to version 2.40.6 or later (e.g., apt update && apt upgrade webkitgtk-4.1 on Debian/Ubuntu, or dnf update webkitgtk4 on Fedora)
  3. 3. Verify the upgrade was successful by checking the new version matches or exceeds 2.40.6
  4. 4. Restart any applications that use WebKitGTK (such as browsers like Epiphany, or other GTK-based applications) to ensure the patched library is loaded
  5. 5. Alternatively, if the distribution does not yet have 2.40.6+ in its repositories, consider upgrading to a newer distribution release that includes a patched WebKitGTK version
Caveat Minor: Upgrading WebKitGTK within the 2.40.x stable branch should have minimal breaking changes; however, ensure dependent applications are compatible

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

Fix this in Debian Linux Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2023-39928 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