Post-Auth Unsafe Deserialization on BasePage (AJAX)

CVE-2021-21247

What is CVE-2021-21247?

OneDev is an all-in-one devops platform. In OneDev before version 4.0.3, the application's BasePage registers an AJAX event listener (AbstractPostAjaxBehavior) in all pages other than the login page. This listener decodes and deserializes the data query parameter. We can access this listener by submitting a POST request to any page. This issue may lead to post-auth RCE This endpoint is subject to authentication and, therefore, requires a valid user to carry on the attack. This issue was addressed in 4.0.3 by encrypting serialization payload with secrets only known to server.

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