Description
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. ioa_addr_is_loopback checks for the literal IPv6 loopback shape before IPv4-mapped IPv6 handling, so good_peer_addr 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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| coturn | coturn | < 4.13.0 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | coturn | 4.14.0-1 | — |
| Debian 13 | coturn | No fix yet | — |
| Debian 12 | coturn | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | coturn | No fix yet | — |
| Ubuntu 26.04 LTS | coturn | No fix yet | — |
| Ubuntu 24.04 LTS | coturn | No fix yet | — |
| Ubuntu 22.04 LTS | coturn | No fix yet | — |
| Ubuntu 20.04 LTS | coturn | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | coturn | No fix yet | — |
| Ubuntu 16.04 LTS | coturn | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | coturn | 4.17.2-1.1 | openSUSE-SU-2026:11617-1 |
Advisories 1
- openSUSE-SU-2026:11617-1 coturn-4.17.2-1.1 on GA media SUSE / openSUSE Security Updates · Aug 28, 2026