Detections
Analytics

CVE-2021-21392

high

Description

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.

References

https://pypi.org/project/matrix-synapse/

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/

https://github.com/matrix-org/synapse/security/advisories/GHSA-5wrh-4jwv-5w78

https://github.com/matrix-org/synapse/pull/9240

Details

Source: Mitre, NVD

Published: 2021-04-12

Updated: 2024-11-21

Risk Information

CVSS v2

Base Score: 4.9

Vector: CVSS2#AV:N/AC:M/Au:S/C:P/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 6.3

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:N

Severity: Medium

CVSS v4

Base Score: 7.1

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

Severity: High

EPSS

EPSS: 0.002