CVE-2026-48796 CefSharp: `FolderSchemeHandlerFactory` path boundary check can expose files outside the configured root folder
Attackers can read files outside the intended root directory in applications using CefSharp's FolderSchemeHandlerFactory due to insufficient path boundary checks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-48796?
CVE-2026-48796 is a medium-severity path traversal vulnerability in CefSharp, published on 18 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
CefSharp provides .NET bindings for the Chromium Embedded Framework for Windows Forms and Windows Presentation Foundation applications. Prior to version 148.0.90, CefSharp/SchemeHandler/FolderSchemeHandlerFactory.cs used filePath.StartsWith(rootFolder, StringComparison.OrdinalIgnoreCase) to decide whether a decoded and canonicalized request path remained inside rootFolder. That raw prefix test did not enforce a directory boundary, so a request such as ..%2fwww2/secret.txt could escape a configured www directory into a sibling www2 directory whose path shared the same string prefix. Applications that register FolderSchemeHandlerFactory for a custom scheme or an HTTP or HTTPS scheme can therefore serve local files outside the intended root when an attacker can cause the embedded browser to request the crafted URL. The issue affects both Unix-style paths such as /tmp/app/www2 and Windows paths such as C:\app\www2, and the fix appends a directory separator to the normalized root before comparison while rejecting null bytes and alternate data stream syntax. This issue is fixed in version 148.0.90.
Weakness: CWE-22
Which versions are affected by CVE-2026-48796?
2 open source packages ship an affected version, including CefSharp.Common.
| Package | Affected | Fixed in |
|---|---|---|
CefSharp.Common NuGet | All versions | 148.0.90 |
CefSharp.Common NuGet | All versions | 148.0.90 |
How do I fix CVE-2026-48796?
Upgrade CefSharp.Common to 148.0.90 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-48796 being exploited?
There is no known exploitation of CVE-2026-48796 in the wild and no public exploit code.
Sources
Also known as GHSA-85jm-cwp2-mvpv.