Open redirect via transitional IPv6 addresses on dual-stack networks
CVE-2021-21392

6.3MEDIUM

Key Information:

Vendor

Matrix-org

Status
Synapse
Vendor
CVE Published:
12 April 2021

What is CVE-2021-21392?

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.

Affected Version(s)

synapse < 1.28.0

References

https://pypi.org/project/matrix-synapse/
x_refsource_MISC
https://github.com/matrix-org/synapse/security/advisories...
x_refsource_CONFIRM
https://github.com/matrix-org/synapse/pull/9240
x_refsource_MISC

CVSS V3.1

Score:
6.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
High
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.