CVE-2021-21392
Published: 12 April 2021
Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.28.0 requests to user provided domains were not restricted to external IP addresses when transitional IPv6 addresses were used. Outbound requests to federation, identity servers, when calculating the key validity for third-party invite events, sending push notifications, and generating URL previews are affected. This could cause Synapse to make requests to internal infrastructure on dual-stack networks. See referenced GitHub security advisory for details and workarounds.
Priority
Status
| Package | Release | Status |
|---|---|---|
|
matrix-synapse Launchpad, Ubuntu, Debian |
bionic |
Needed
|
| focal |
Needed
|
|
| groovy |
Ignored
(end of life)
|
|
| hirsute |
Ignored
(end of life)
|
|
| impish |
Ignored
(end of life)
|
|
| jammy |
Needed
|
|
| kinetic |
Ignored
(end of life, was needed)
|
|
| lunar |
Not vulnerable
(1.64.0-3)
|
|
| mantic |
Not vulnerable
(1.64.0-3)
|
|
| trusty |
Does not exist
|
|
| upstream |
Released
(1.28.0-1)
|
|
| xenial |
Does not exist
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 6.3 |
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | Low |
| User interaction | Required |
| Scope | Unchanged |
| Confidentiality | Low |
| Integrity impact | High |
| Availability impact | None |
| Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:N |