CVE-2020-26262

Published Jan 13, 2021

Last updated a year ago

Overview

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.
Source
security-advisories@github.com
NVD status
Modified

Risk scores

CVSS 3.1

Type
Primary
Base score
7.2
Impact score
2.7
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Severity
HIGH

CVSS 2.0

Type
Primary
Base score
6.4
Impact score
4.9
Exploitability score
10
Vector string
AV:N/AC:L/Au:N/C:P/I:P/A:N

Weaknesses

security-advisories@github.com
CWE-441

Social media

Hype score
Not currently trending

Configurations