Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, an unauthenticated remote client can send a STUN message over TCP or TLS with a body-length field from 65520 through 65532, causing the uint16t len variable in stungetmessagelenstr() in src/client/nsturnmsg.c to wrap when STUNHEADERLENGTH is added. The framing layer then consumes only 4 through 16 bytes, treats the remaining bytes as another message, desynchronizes the stream parser, and drops the attacking client's connection. Other clients and the server process are not affected. This issue is fixed in version 4.15.0.

Coturn is a free open source implementation of TURN and STUN Server. In 4.15.0, an authenticated TURN user can repeatedly resume one allocation from fresh UDP 5-tuples without completing a handoff when the server enables --mobility. mobilebegintransition() in src/server/nsturnserver.c disarms each new session's allocation timeout and overwrites the allocation's single mobilependingresume link, leaving earlier pending sessions unreachable by the cleanup path, while copyauthparameters() ignores incquota() failure. The attacker can therefore retain unbounded server-side sessions and exhaust process memory even when --user-quota=1 is configured. This issue is fixed in version 4.16.0.

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 issecurestring() validation and is embedded into Redis keys at nine call sites in src/apps/relay/nsioalibengineimpl.c. sendmessagetoredis() in src/apps/relay/hiredislibevent2.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 valist. 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 4.15.0, an on-path attacker can append attributes after MESSAGE-INTEGRITY to an authenticated STUN request on plain UDP or TCP, adjust the STUN header length, and recompute the unkeyed FINGERPRINT while the original HMAC remains valid because it covers only the message prefix. Server-side parsing in src/server/nsturnserver.c continues past MESSAGE-INTEGRITY through handleturnallocate(), handleturncreatepermission(), handleturnrefresh(), and handleturncommand(), allowing trailing LIFETIME, XOR-PEER-ADDRESS, or ORIGIN attributes to override allocation lifetime, inject a permission, or bypass the origin check. TLS and DTLS deployments prevent this in-transit modification. This issue is fixed in version 4.15.0.

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.17.0, turnportsallocateeven() in src/apps/relay/turnports.c marks the unused odd sibling port as TPSTAKENODD 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, addrlesseq() in src/client/nsturnioaddr.c uses a component-wise comparison for native IPv6 min-max intervals in ioaaddrinrange(), allowing an authenticated TURN client to relay to an IPv6 peer that is numerically within a configured non-prefix-aligned denied-peer-ip range but is classified as outside it. This issue is fixed in version 4.16.0.

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.16.0, dtlsserverinputhandler() and createnewconnectedudpsocket() in src/apps/relay/dtlslistener.c retain OpenSSL dtls1reassemblefragment() 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 4.17.0, shutdownclientconnection() in src/server/nsturnserver.c prematurely calls decquota() and releases bandwidth accounting during the first-stage close of a mobility-enabled allocation while preserving the allocation, relay socket, session, and mobility ticket, allowing an authenticated client to bypass --user-quota and --total-quota and exhaust relay ports. This issue is fixed in version 4.17.0.

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.13.1, goodpeeraddr() in src/server/nsturnserver.c uses ioaaddrinrange() in src/client/nsturnioaddr.c without canonicalizing IPv4-compatible, 6to4, and 64:ff9b::/96 NAT64 address forms, allowing an authenticated RFC 6062 TCP CONNECT relay client to bypass an IPv4 denied-peer-ip range when the Coturn host has a useful translation route. This issue is fixed in version 4.13.1.

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 handleturnrefresh resume branch, the victim allocation (origss) is located solely by the attacker-controlled mobile id, and credentials are only adopted (via copyauthparameters) when the resuming session is unauthenticated. Because the attacker's session already has hmackeyset set to 1 from its own prior authentication (which is never reset for long-term-credential sessions), the credential copy is skipped and checkstunauth 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.

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.13.0, coturn rejects loopback peers by default unless allow-loopback-peers is enabled, but the default loopback guard can be bypassed by using the IPv4-mapped IPv6 peer address ::ffff:127.0.0.1 in a TURN XOR-PEER-ADDRESS attribute. ioaaddrisloopback checks for the literal IPv6 loopback shape before IPv4-mapped IPv6 handling, so goodpeeraddr does not apply the default loopback rejection and an authenticated TURN client can expose services bound only to localhost on the coturn host through TURN relay traffic. This issue is fixed in version 4.13.0.

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.12.0, the coturn HTTPS admin panel passes HTTP query parameters directly into SQL queries via snprintf string interpolation without sanitization. The issecurestring filter that protects the STUN protocol path is not applied to the admin panel's delete-user, delete-secret, and delete-IP operations, so an authenticated admin can inject arbitrary SQL through the du, ds, and dip parameters, gaining full database control and potentially OS-level access via PostgreSQL COPY TO PROGRAM. This issue is fixed in version 4.12.0.

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.13.0, the psd print sessions dump CLI command in coturn takes a filename argument and directly passes it to fopen with no path validation. An authenticated admin with CLI access can overwrite arbitrary files writable by the coturn process because the command string is used as-is after stripping the psd prefix and leading spaces, allowing truncation and overwrite with session dump data. This issue is fixed in version 4.13.0.

Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.11.0 contain a stored cross-site scripting (XSS) vulnerability in the web-admin HTTPS interface. An attacker who can create a TURN allocation with a crafted USERNAME value can inject HTML/JavaScript that executes when an authenticated web-admin user views the TURN session list. In configurations using anonymous TURN access (--no-auth), this may be exploitable without TURN credentials. In authenticated deployments, exploitation requires valid TURN credentials or control over a provisioned username. This issue has been fixed in version 4.11.0.

Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.10.0 contain a stack buffer overflow in decodeoauthtokengcm(). A uint16t noncelen field read from an attacker-supplied OAuth access token (0-65535) is passed directly to memcpy() as the copy length into a 256-byte stack buffer (oauthencryptedblock.nonce[256]) without bounds checking. The overflow occurs before AES-GCM authentication is verified, the attacker does not need to know the OAuth key or produce a valid AES-GCM token. Up to 735 bytes of attacker-controlled data are written past the buffer, may corrupt adjacent stack data, including control-flow data depending on compiler, ABI, and mitigations. Requires --oauth mode (non-default). This may provide a plausible RCE primitive depending on exploit mitigations; because coturn is widely deployed for WebRTC TURN/STUN and --oauth is commonly recommended, impact can be broad. This issue has been fixed in version 4.10.0.

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.10.0, the STUN/TURN attribute parsing functions in coturn perform unsafe pointer casts from uint8t to uint16t without alignment checks. When processing a crafted STUN message with odd-aligned attribute boundaries, this results in misaligned memory reads at nsturnmsg.c. On ARM64 architectures (AArch64) with strict alignment enforcement, this causes a SIGBUS signal that immediately kills the turnserver process. An unauthenticated remote attacker can crash any ARM64 coturn deployment by sending a single crafted UDP packet. This vulnerability is fixed in 4.10.0.