CefSharp: `FolderSchemeHandlerFactory` path boundary check can expose files outside the configured root folder

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-48796
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-18 22:16:52 UTC
Updated2026-08-19 19:17:17 UTC
DescriptionCefSharp 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.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

EPSS: 0.002930000 probability, percentile 0.219020000 (date 2026-08-20)

Problem Types: CWE-22 | CWE-22 CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
3.1CNADECLARED5.3MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Cefsharp CefSharp affected < 148.0.90 Not specified

References

ReferenceSourceLinkTags
github.com/cefsharp/CefSharp/releases/tag/v148.0.90 [email protected] github.com
github.com/cefsharp/CefSharp/security/advisories/GHSA-85jm-cwp2-mvpv [email protected] github.com
github.com/cefsharp/CefSharp/commit/3475c7ef14119f67ec3720866bb3e4b1c6c6... [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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