CVE-2021-21242

CVE-2021-21242 is a critical pre-authentication remote code execution vulnerability affecting OneDev versions prior to 4.0.3. The flaw stems from the AttachmentUploadServlet deserializing untrusted data from the Attachment-Support header without authentication or authorization checks. With a CVSS score of 9.8, this vulnerability allows an unauthenticated attacker to achieve full compromise of the affected system with low attack complexity. While there is no evidence of active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB), the vulnerability has garnered significant community discussion with 10 mentions, indicating awareness and potential interest among researchers.