The RemoteControl API methods invite_participants and remind_participants pass a caller-supplied token-ID array into TokenDynamic::findUninvited(), which concatenates the values directly into a tid IN ('...') SQL clause without parameterization or input validation. A remote, authenticated attacker holding the tokens/update permission on a survey can inject a crafted array element to perform SQL injection. Because LimeSurvey configures its PDO connection with emulated prepared statements (emulatePrepare = true) and does not disable MySQL multi-statements, the injection supports stacked queries: the attacker can append arbitrary additional statements (INSERT/UPDATE/DELETE/DROP/CREATE) after the original SELECT. This permits both arbitrary read of any data in the database, such as administrator bcrypt password hashes (lime_users), survey response PII, session records, and global settings, all recoverable via a SLEEP() time-based blind oracle, and arbitrary write/destruction of that data, including directly overwriting the administrator password hash for immediate account takeover or dropping/truncating tables. Reads and writes extend to any schema the application's database user can access. The RemoteControl interface (RPCInterface = json/xml) must be enabled, which is not the default.

LimeSurvey constructs account password-reset links from the client-supplied HTTP Host header without validating it. The optional allowedHosts allowlist that would constrain this is undefined in the default (and documented) configuration, so LSHttpRequest::checkIsAllowedHost() results in no operation. A remote, unauthenticated attacker who submits a forgotten-password request for a known account (requiring only the target's username and email) with a spoofed Host header causes LimeSurvey to email that account a reset link whose hostname is attacker-controlled while embedding the genuine validation_key. When the recipient or an automated inbound mail-security link scanner dereferences the link, the valid reset token is disclosed to the attacker, who replays it against the legitimate host's newPassword endpoint to set a new password and take over the account.