Coturn

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.13.0, an authenticated TURN user can place printf-style format specifiers in the STUN USERNAME or REALM attribute, which passes is_secure_string() validation and is embedded into Redis keys at nine call sites in src/apps/relay/ns_ioalib_engine_impl.c. send_message_to_redis() in src/apps/relay/hiredis_libevent2.c then passes the attacker-controlled key as the format argument to redisAsyncCommand() while supplying only one variadic value, causing hiredis redisvFormatCommand() to read past the va_list. Exploitation can crash the coturn process and terminate active TURN sessions or disclose stack memory into Redis. This issue is fixed in version 4.13.0.

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.17.0, turnports_allocate_even() in src/apps/relay/turn_ports.c marks the unused odd sibling port as TPS_TAKEN_ODD for an EVEN-PORT Allocate request with reservation bit R=0 even though no RTCP socket will release it, allowing an authenticated client to permanently exhaust the relay port pool and cause subsequent allocations to fail with STUN error 508. This issue is fixed in version 4.17.0.

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.16.0, dtls_server_input_handler() and create_new_connected_udp_socket() in src/apps/relay/dtls_listener.c retain OpenSSL dtls1_reassemble_fragment() state for a 35-byte fragmented ClientHello declaring a 650,000-byte handshake before cookie validation, allowing an unauthenticated remote sender using fresh UDP tuples to exhaust memory without TURN credentials, a completed handshake, a valid cookie, or source spoofing. This issue is fixed in version 4.16.0.

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, a server using --mobility authenticates a resumed REFRESH request with the resuming user's credentials but does not verify that identity against the original allocation owner, allowing an authenticated attacker who obtains a victim MOBILITY-TICKET to receive and inject relayed traffic and consume the victim's quota. In the handle_turn_refresh resume branch, the victim allocation (orig_ss) is located solely by the attacker-controlled mobile id, and credentials are only adopted (via copy_auth_parameters) when the resuming session is unauthenticated. Because the attacker's session already has hmackey_set set to 1 from its own prior authentication (which is never reset for long-term-credential sessions), the credential copy is skipped and check_stun_auth validates the REFRESH against the attacker's own identity rather than the allocation owner's. This issue is fixed in version 4.15.0.

Coturn is a free open source implementation of TURN and STUN Server. From 4.5.2 through 4.14.0, when Coturn is started with --acme-redirect <URL> and exposes a plaintext-TCP listener, an unauthenticated remote client can send a single ordinary HTTP GET request and receive a 301 response whose Location header contains up to ~870 bytes of adjacent process heap memory. The leaked region is a recycled network receive buffer that is reused without being zeroed, so on a busy server it can contain data from other clients' requests (TURN credentials, OAuth tokens, relayed payloads). Root cause is a signed→unsigned conversion. This issue is fixed in version 4.15.0.