Vulnerability Description
Coturn is free open source implementation of TURN and STUN Server. Coturn before version 4.5.2 by default does not allow peers to connect and relay packets to loopback addresses in the range of `127.x.x.x`. However, it was observed that when sending a `CONNECT` request with the `XOR-PEER-ADDRESS` value of `0.0.0.0`, a successful response was received and subsequently, `CONNECTIONBIND` also received a successful response. Coturn then is able to relay packets to the loopback interface. Additionally, when coturn is listening on IPv6, which is default, the loopback interface can also be reached by making use of either `[::1]` or `[::]` as the peer address. By using the address `0.0.0.0` as the peer address, a malicious user will be able to relay packets to the loopback interface, unless `--denied-peer-ip=0.0.0.0` (or similar) has been specified. Since the default configuration implies that loopback peers are not allowed, coturn administrators may choose to not set the `denied-peer-ip` setting. The issue patched in version 4.5.2. As a workaround the addresses in the address block `0.0.0.0/8`, `[::1]` and `[::]` should be denied by default unless `--allow-loopback-peers` has been specified.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Coturn Project | Coturn | < 4.5.2 |
| Fedoraproject | Fedora | 32 |
Related Weaknesses (CWE)
References
- https://github.com/coturn/coturn/blob/57180ab60afcaeb13537e69ae8cb8aefd8f3f546/CRelease NotesThird Party Advisory
- https://github.com/coturn/coturn/commit/abfe1fd08d78baa0947d17dac0f7411c3d948e4dPatchThird Party Advisory
- https://github.com/coturn/coturn/security/advisories/GHSA-6g6j-r9rf-cm7pExploitThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://github.com/coturn/coturn/blob/57180ab60afcaeb13537e69ae8cb8aefd8f3f546/CRelease NotesThird Party Advisory
- https://github.com/coturn/coturn/commit/abfe1fd08d78baa0947d17dac0f7411c3d948e4dPatchThird Party Advisory
- https://github.com/coturn/coturn/security/advisories/GHSA-6g6j-r9rf-cm7pExploitThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
FAQ
What is CVE-2020-26262?
CVE-2020-26262 is a vulnerability with a CVSS score of 7.2 (HIGH). Coturn is free open source implementation of TURN and STUN Server. Coturn before version 4.5.2 by default does not allow peers to connect and relay packets to loopback addresses in the range of `127.x...
How severe is CVE-2020-26262?
CVE-2020-26262 has been rated HIGH with a CVSS base score of 7.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2020-26262?
Check the references section above for vendor advisories and patch information. Affected products include: Coturn Project Coturn, Fedoraproject Fedora.