Authentication bypass via second StartupMessage during SCRAM authentication in PgBouncer

An infinite loop in PgBouncer 1.20.0 through 1.26.0 allows an unauthenticated remote attacker to cause a denial of service. A StartupMessage whose options parameter contains an empty parameter name, such as "-c=", makes the ignorestartupparameters list lookup loop forever. Because PgBouncer serves all clients from a single process, this saturates a CPU core and makes PgBouncer unresponsive to all clients until the process is restarted.

Integer overflow causes an infinite loop in message buffer growth in PgBouncer

Missing validation of a mandatory attribute in the SCRAM client-final-message parser in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to crash the process. A malformed message can make the parser report success while leaving a required value unset, which is then dereferenced as a NULL pointer. The crash occurs before any credential is verified, so no valid account is required. Because PgBouncer serves all clients from a single process, this terminates every pooled connection.

Missing upper bound on the key derivation iteration count accepted during SCRAM authentication to a backend server in PgBouncer through 1.25.2 allows a malicious or compromised PostgreSQL backend to cause uncontrolled CPU consumption in PgBouncer. The resulting key derivation cannot be interrupted in frontend builds such as PgBouncer. Because PgBouncer serves all clients from a single process, one backend can in this way stop it from serving traffic for every other database and client it is pooling, so the failure of a single backend is not contained.

Integer overflow causes an infinite loop in packet buffer growth in PgBouncer

PgBouncer before 1.25.2 did not perform an appropriate authorization check for the KILLCLIENT admin command. All users with access to the administration console (which itself requires authorization) could run this command. It would have been correct to allow only users listed in the adminusers parameter.

A possible null pointer reference in PgBouncer before 1.25.2 could lead to a crash, if a server sends an error response without SQLSTATE field.

PgBouncer buffer overflow in SCRAM

An integer overflow in network packet parsing code in PgBouncer before 1.25.2 bypasses a boundary check and can lead to a crash. An unauthenticated remote attacker can crash PgBouncer with a malformed SCRAM authentication packet.

Untrusted search path in authquery connection handler in PgBouncer before 1.25.1 allows an unauthenticated attacker to execute arbitrary SQL during authentication via a malicious searchpath parameter in the StartupMessage.

Password can be used past expiry in PgBouncer due to authquery not taking into account Postgres its VALID UNTIL value, which allows an attacker to log in with an already expired password