LimeSurvey through 6.17.10 and 7.0.4 contains a server-side request forgery vulnerability in the REST API survey template endpoint that allows authenticated users to cause the server to issue arbitrary HTTP requests by supplying a manipulated Host header. Attackers can exploit the unsanitized use of the HTTP Host header in the getTemplateData() function to reach internal network services, cloud metadata endpoints, and extract sensitive credentials such as IAM tokens from instance metadata services.

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.

In version 6.13.0 of LimeSurvey, any external user can cause a 500 error in the survey system by sending a malformed session cookie. Instead of displaying a generic error message, the system exposes internal backend information, including the use of the Yii framework, the MySQL/MariaDB database engine, the table name 'lime_sessions', primary keys, and fragments of the content that caused the conflict. This information can simplify the collection of data about the internal architecture of the application by an attacker.

Vulnerability in LimeSurvey 6.13.0 in the endpoint /optin that causes infinite HTTP redirects when accessed directly. This behavior can be exploited to generate a Denegation of Service (DoS attack), by exhausting server or client resources. The system is unable to break the redirect loop, which can cause service degradation or browser instability.

Vulnerability in LimeSurvey 6.13.0 in the endpoint /optout that causes infinite HTTP redirects when accessed directly. This behavior can be exploited to generate a Denegation of Service (DoS attack), by exhausting server or client resources. The system is unable to break the redirect loop, which can cause service degradation or browser instability.

CRLF Injection vulnerability in Limesurvey v2.65.1+170522.  This vulnerability could allow a remote attacker to inject arbitrary HTTP headers and perform HTTP response splitting attacks via '/index.php/survey/index/sid/<SID>/token/fwyfw%0d%0aCookie:%20POC'.

SQL Injection vulnerability in Limesurvey v2.65.1+170522. This vulnerability allows an attacker to retrieve, create, update and delete database via 'token' parameter in '/index.php' endpoint.