{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/tags/code16/sharp/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":[],"_cs_severities":["high"],"_cs_tags":["laravel","file-upload","rce","code16/sharp"],"_cs_type":"advisory","_cs_vendors":[],"content_html":"\u003cp\u003eThe \u003ccode\u003ecode16/sharp\u003c/code\u003e Laravel admin panel package, specifically versions before 9.20.0, is vulnerable to unrestricted file upload. An authenticated user can manipulate the \u003ccode\u003evalidation_rule\u003c/code\u003e parameter in the \u003ccode\u003e/api/form/upload\u003c/code\u003e endpoint to bypass file type restrictions. This vulnerability stems from insufficient server-side validation of the client-supplied \u003ccode\u003evalidation_rule\u003c/code\u003e, which is directly passed to the Laravel validator. Successfully exploiting this vulnerability allows an attacker to upload arbitrary files, including PHP webshells, which can lead to remote code execution (RCE) if the storage disk is publicly accessible. The vulnerability was reported by zaurgsynv and has been patched in pull request #714. Defenders should ensure their Sharp instances are updated to version 9.20.0 or later, and restrict disk access.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn authenticated user logs into the Sharp Laravel admin panel.\u003c/li\u003e\n\u003cli\u003eThe user navigates to a section of the application that utilizes the file upload functionality.\u003c/li\u003e\n\u003cli\u003eThe user intercepts the HTTP request sent to the \u003ccode\u003e/api/form/upload\u003c/code\u003e endpoint.\u003c/li\u003e\n\u003cli\u003eThe user modifies the request body, specifically the \u003ccode\u003evalidation_rule\u003c/code\u003e parameter, setting it to \u003ccode\u003evalidation_rule[]=file\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe modified request is sent to the server, bypassing MIME type and file extension checks.\u003c/li\u003e\n\u003cli\u003eThe server processes the upload request, saving the arbitrary file (e.g., a PHP webshell) to the designated storage disk.\u003c/li\u003e\n\u003cli\u003eIf the storage disk is publicly accessible, the attacker can access the uploaded file via a web browser.\u003c/li\u003e\n\u003cli\u003eThe attacker executes the uploaded PHP webshell, achieving remote code execution (RCE) on the server.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of this vulnerability allows attackers to upload arbitrary files, including PHP webshells, to the affected server. This can lead to Remote Code Execution (RCE) if the server\u0026rsquo;s storage disk is misconfigured to be publicly accessible. While default configurations prevent direct execution of uploaded PHP files, compromised servers can be leveraged for lateral movement, data exfiltration, or further malicious activities. This vulnerability impacts all installations of \u003ccode\u003ecode16/sharp\u003c/code\u003e prior to version 9.20.0.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eUpgrade \u003ccode\u003ecode16/sharp\u003c/code\u003e to version 9.20.0 or later to remediate CVE-2026-33687.\u003c/li\u003e\n\u003cli\u003eEnsure that the storage disk used for Sharp uploads is strictly private, as described in the Laravel filesystem documentation (\u003ca href=\"https://laravel.com/docs/13.x/filesystem)\"\u003ehttps://laravel.com/docs/13.x/filesystem)\u003c/a\u003e.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Sharp File Upload Bypass Attempt\u0026rdquo; to identify attempts to exploit this vulnerability based on the \u003ccode\u003evalidation_rule\u003c/code\u003e parameter.\u003c/li\u003e\n\u003cli\u003eMonitor web server logs for suspicious file uploads to the \u003ccode\u003e/api/form/upload\u003c/code\u003e endpoint, correlating with user activity and file extensions.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-03-25T20:03:11Z","date_published":"2026-03-25T20:03:11Z","id":"/briefs/2026-06-sharp-file-upload-bypass/","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 by manipulating the validation_rule parameter, potentially leading to Remote Code Execution (RCE) if the storage disk is configured to be publicly accessible.","title":"Sharp Laravel Admin Panel Unrestricted File Upload Vulnerability","url":"https://feed.craftedsignal.io/briefs/2026-06-sharp-file-upload-bypass/"}],"language":"en","title":"CraftedSignal Threat Feed — Code16/Sharp","version":"https://jsonfeed.org/version/1.1"}