# 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.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N`)
- **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:** Yes
- **Published:** 18 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** GHSA-85jm-cwp2-mvpv

## 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 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-48796?

2 open source packages ship an affected version, including CefSharp.Common.


| Package | Ecosystem | 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.

## Is CVE-2026-48796 being exploited?

There is no known exploitation of CVE-2026-48796 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48796 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-48796 in the wild and no public exploit code.

Affected packages and fixed versions:
- CefSharp.Common (NuGet): affected all versions; fixed in 148.0.90
- CefSharp.Common (NuGet): affected all versions; fixed in 148.0.90

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-48796/ (Markdown: https://insights.sbomify.com/CVE-2026-48796/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48796
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48796
- OSV: https://osv.dev/vulnerability/CVE-2026-48796

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48796/
Summaries are generated and may contain mistakes; the official description above is the record.