code16 Sharp is a Laravel-based framework for building content-management and administrative interfaces. Versions before 9.22.5 contain a stored cross-site scripting vulnerability in the rich-text editor because the HTML sanitizer permits the srcdoc attribute on iframe elements. Although markup inside srcdoc is HTML-encoded during sanitization, browsers decode attribute entities before interpreting the iframe document, allowing an authenticated user with permission to edit an Editor field to store executable JavaScript that runs when another user views the content. Successful exploitation can result in session hijacking, unauthorized actions, account takeover, privilege escalation, or disclosure of administrative data. Version 9.22.5 patches the vulnerability by removing srcdoc from the permitted iframe attributes. As a workaround, applications that cannot upgrade should manually sanitize all Editor field content and remove every iframe srcdoc attribute before storing or rendering it.

Summary A path traversal vulnerability exists in the FileUtil class of the code16/sharp package. The application fails to sanitize file extensions properly, allowing path separators to be passed into the storage layer.

Detail In src/Utils/FileUtil.php, the FileUtil::explodeExtension() function extracts a file's extension by splitting the filename at the last dot. However, the extracted extension is never sanitized. While the application uses a normalizeName() function, this function only cleans the base filename, meaning any path separators (such as /) injected into the extension will survive and be passed into the storeAs() function.

Impact Exploiting this flaw allows an authenticated attacker to manipulate file paths: - Files can be written outside of the intended tmp directory via path traversal. For more details on the package, visit: https://github.com/code16/sharp - Existing critical files (such as .env or configuration files) could potentially be overwritten. Review the CWE definition here: https://cwe.mitre.org/data/definitions/22.html (Note: This vulnerability was successfully chained with CWE-434 in a local Proof of Concept to confirm the traversal.)

Patches This issue has been patched by properly sanitizing the extension using pathinfo(PATHINFOEXTENSION) instead of strrpos(), alongside applying strict regex replacements to both the base name and the extension. The fix is available in pull request #715

Credits Reported by zaurgsynv.

Summary The code16/sharp Laravel admin panel package contains a vulnerability in its file upload endpoint that allows authenticated users to bypass all file type restrictions.

Details The upload endpoint within the ApiFormUploadController accepts a client-controlled validationrule parameter. This parameter is directly passed into the Laravel validator without sufficient server-side enforcement. By intercepting the request and sending validationrule[]=file, an attacker can completely bypass all MIME type and file extension restrictions. The vulnerable code is located in src/Http/Controllers/Api/ApiFormUploadController.php at line 24.

Impact This vulnerability leads to several critical security risks:

Attackers can upload arbitrary files, including PHP webshells, to the server. For more details on the package, visit: https://github.com/code16/sharp

MIME type and extension validation can be bypassed entirely via client-controlled rules. Review the CWE definition here: https://cwe.mitre.org/data/definitions/434.html

If the storage disk is configured to be publicly accessible, this can lead to Remote Code Execution (RCE). See the vendor repository: https://github.com/code16/sharp

(Note: Under default configurations, executing uploaded PHP files directly is not possible unless a public disk configuration is in place.)

Patches This issue has been addressed by removing the client-controlled validation rules and strictly defining upload rules server-side. The fix is available in pull request https://github.com/code16/sharp/pull/714.

Workarounds - Restrict Disk Access: Ensure that the storage disk used for Sharp uploads is strictly private. Under default configurations, an attacker cannot directly execute uploaded PHP files unless a public disk configuration is explicitly used. For more details on Laravel disk configurations, visit: https://laravel.com/docs/13.x/filesystem

Credits Reported by zaurgsynv.