{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/tags/dotvvm/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["DotVVM (\u003c 4.2.11)","DotVVM (\u003e 4.3.0-preview01-final, \u003c 4.3.15)","DotVVM (\u003e= 5.0.0-preview01-final, \u003c 5.0.0-preview09-final)"],"_cs_severities":["critical"],"_cs_tags":["authorization-bypass","web-application","vulnerability","dotvvm"],"_cs_type":"advisory","_cs_vendors":["DotVVM"],"content_html":"\u003cp\u003eA critical authorization bypass vulnerability (GHSA-c8qj-jx8j-fg2w) has been identified in the \u003ccode\u003eAuthorizeActionFilter\u003c/code\u003e class within the DotVVM framework. This flaw affects all users who have implemented the \u003ccode\u003eAuthorizeActionFilter\u003c/code\u003e to secure parts of their web applications. The component, intended to enforce access controls, is inherently flawed and performs no actual authorization checks, effectively allowing any request to bypass the filter and access protected resources. This vulnerability does not require complex 'hacking' techniques; an attacker simply needs to make a standard request to a supposedly protected endpoint, and the filter will mistakenly grant access. This flaw impacts DotVVM versions prior to 4.2.11, between 4.3.0-preview01-final and 4.3.15, and between 5.0.0-preview01-final and 5.0.0-preview09-final.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003e\u003cstrong\u003eAttacker identifies target application:\u003c/strong\u003e An attacker identifies a web application that is developed using the DotVVM framework.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eVulnerability discovery:\u003c/strong\u003e The attacker becomes aware of the \u003ccode\u003eAuthorizeActionFilter\u003c/code\u003e authorization bypass vulnerability (GHSA-c8qj-jx8j-fg2w) in DotVVM, understanding its nature as a complete bypass.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eEndpoint identification:\u003c/strong\u003e The attacker probes or researches the target application to identify specific web application endpoints or functionalities that are intended to be protected by the vulnerable \u003ccode\u003eAuthorizeActionFilter\u003c/code\u003e (e.g., \u003ccode\u003e/admin\u003c/code\u003e, \u003ccode\u003e/dashboard\u003c/code\u003e, \u003ccode\u003e/api/users\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eCraft unauthorized request:\u003c/strong\u003e The attacker crafts a standard HTTP GET or POST request to one of these identified protected endpoints, intentionally omitting or providing insufficient authentication or authorization tokens.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eApplication processes request:\u003c/strong\u003e The vulnerable DotVVM application receives and processes the crafted HTTP request, routing it to the appropriate controller action.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eFilter execution (no check):\u003c/strong\u003e The \u003ccode\u003eAuthorizeActionFilter\u003c/code\u003e component, despite being invoked for the protected endpoint, executes without performing any authorization validation due to its internal flaw, effectively doing nothing.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eUnauthorized access granted:\u003c/strong\u003e The DotVVM application, mistakenly assuming authorization has occurred, proceeds to execute the action and grants the attacker full access to the intended protected resource or functionality.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eImpact achieved:\u003c/strong\u003e The attacker successfully bypasses security controls, leading to unauthorized data exposure, privilege escalation, or the ability to perform restricted actions within the compromised application.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eAll applications utilizing the \u003ccode\u003eAuthorizeActionFilter\u003c/code\u003e class within the specified vulnerable DotVVM versions are at critical risk. The complete failure of the filter to perform any authorization checks means that any resource or functionality intended to be protected by it is openly accessible to unauthorized individuals. This directly leads to unauthorized access to sensitive data, compromise of administrative functions, or complete takeover of application features that were meant to be restricted. The number of potentially affected applications is widespread among DotVVM users who relied on this specific authorization mechanism for security.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003ePatch immediately:\u003c/strong\u003e Upgrade all affected DotVVM installations to a patched version (DotVVM 4.3.15, 4.2.11, or 5.0.0-preview09) to remediate the GHSA-c8qj-jx8j-fg2w vulnerability.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eImplement workaround:\u003c/strong\u003e For immediate protection if patching is not feasible, replace all instances of \u003ccode\u003eAuthorizeActionFilter\u003c/code\u003e with \u003ccode\u003eAuthorizeAttribute\u003c/code\u003e in your DotVVM application code.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eMonitor webserver logs:\u003c/strong\u003e Deploy the Sigma rules \u0026quot;Detect Successful Access to Common Sensitive Web GET Paths\u0026quot; and \u0026quot;Detect Successful Access to Common Sensitive Web POST Paths\u0026quot; to monitor for HTTP 200 responses to known administrative or sensitive URIs, as this can indicate potential unauthorized access.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eApplication-level logging:\u003c/strong\u003e Implement robust application-level logging for all sensitive actions and authorization events to identify successful access to resources that should require specific permissions.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-06-19T15:15:34Z","date_published":"2026-06-19T15:15:34Z","id":"https://feed.craftedsignal.io/briefs/2026-06-dotvvm-auth-bypass/","summary":"A critical authorization bypass vulnerability exists in the `AuthorizeActionFilter` class within the DotVVM framework, failing to perform any authorization checks and allowing attackers to bypass intended access restrictions without specific exploitation techniques, impacting all users relying on `AuthorizeActionFilter` for security. Patched versions include DotVVM 4.3.15, 4.2.11, and 5.0.0-preview09; `AuthorizeAttribute` can be used as a workaround.","title":"DotVVM AuthorizeActionFilter Critical Authorization Bypass","url":"https://feed.craftedsignal.io/briefs/2026-06-dotvvm-auth-bypass/"}],"language":"en","title":"CraftedSignal Threat Feed - Dotvvm","version":"https://jsonfeed.org/version/1.1"}