PT-2026-54441 · Nuget · Cefsharp.Common
Publicado
2026-06-30
·
Atualizado
2026-06-30
·
CVE-2026-48796
CVSS v3.1
5.3
Média
| Vetor | AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N |
Summary
FolderSchemeHandlerFactory was intended to restrict served files to a configured rootFolder, but its path validation used a raw string prefix check. A request could escape to a sibling directory whose full path starts with the root folder path, allowing files outside the configured root to be served.Details
In affected versions,
FolderSchemeHandlerFactory canonicalized rootFolder, decoded the request path, combined it with the root, and then allowed the file when:csharp
filePath.StartsWith(rootFolder, StringComparison.OrdinalIgnoreCase)This does not enforce a directory boundary. For example,
/tmp/app/www2/secret.txt starts with /tmp/app/www, but www2 is a sibling of www, not a child. The same issue applies on Windows, for example C:appwww2secret.txt starts with C:appwww.The affected code was reviewed at commit
b5fef3bb4bc58798c95170078c41de92cfe9066e, assembly version 147.0.100.PoC
Set
rootFolder to a directory named www and create a sibling directory named www2:text
<temp>/www/index.html
<temp>/www2/secret.txtRegister
FolderSchemeHandlerFactory for <temp>/www, then request:text
https://folderschemehandlerfactory.test/..%2fwww2/secret.txtThe request path is URL-decoded to
../www2/secret.txt, combined with <temp>/www, and canonicalized to:text
<temp>/www2/secret.txtBecause
<temp>/www2/secret.txt starts with <temp>/www as a string prefix, the affected check passes and secret.txt is served from outside rootFolder.Expected vulnerable result: HTTP 200 with the contents of
<temp>/www2/secret.txt.Expected fixed result: 404 or equivalent not-found response because the resolved file is outside
rootFolder.Impact
Applications using
FolderSchemeHandlerFactory for a custom scheme or registered HTTP/HTTPS scheme may expose local files outside the intended served directory. This is most relevant when sensitive sibling directories share the root path prefix, such as www/www2, public/public backup, or static/static-secrets.An attacker must be able to cause the embedded browser to request URLs handled by the affected scheme registration.
Correção
Path traversal
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Cefsharp.Common