OpenSIPS versions 3.1 before 3.6.4 containing the auth_jwt module (prior to commit 3822d33) contain a SQL injection vulnerability in the jwt_db_authorize() function in modules/auth_jwt/authorize.c when db_mode is enabled and a SQL database backend is used. The function extracts the tag claim from a JWT without prior signature verification and incorporates the unescaped value directly into a SQL query. An attacker can supply a crafted JWT with a malicious tag claim to manipulate the query result and bypass JWT authentication, allowing impersonation of arbitrary identities.