https://cve.radiocsirt.org/rss/recent/all/10 Most recent entries from all 2026-10-15T17:58:30.483730+00:00 Vulnerability-Lookup csirt@opendfir.org python-feedgen Contains only the most 10 recent entries. https://cve.radiocsirt.org/vuln/euvd-2026-22183 EUVD-2026-22183 2026-10-15T17:58:30.589138+00:00 EUVD-2026-22183 https://cve.radiocsirt.org/vuln/fkie_cve-2021-21392 fkie_cve-2021-21392 2026-10-15T17:58:30.589181+00:00

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.

 https://cve.radiocsirt.org/vuln/ghsa-5wrh-4jwv-5w78 GHSA-5wrh-4jwv-5w78 — Open redirect via transitional IPv6 addresses on dual-stack networks 2026-10-15T17:58:30.589235+00:00

Affected: PyPI: matrix-synapse

### Impact 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.

### Patches This issue is fixed by #9240.

### Workarounds Outbound requests to the following address ranges can be blocked by a firewall, if unused for internal communication between systems:

* `::ffff/80` * `::0000/80` (note that this IP range is considered deprecated by the IETF) * `2002::/16` (note that this IP range is considered deprecated by the IETF)

### References * [RFC3056](https://tools.ietf.org/html/rfc3056) * [RFC4291](https://tools.ietf.org/html/rfc4291)

 https://cve.radiocsirt.org/vuln/gsd-2021-21392 gsd-2021-21392 2026-10-15T17:58:30.589291+00:00 gsd-2021-21392 https://cve.radiocsirt.org/vuln/pysec-2021-25 PYSEC-2021-25 2026-10-15T17:58:30.589311+00:00

Affected: PyPI: matrix-synapse

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.

 https://cve.radiocsirt.org/vuln/ubuntu-cve-2021-21392 UBUNTU-CVE-2021-21392 2026-10-15T17:58:30.589351+00:00

Affected: Ubuntu:Pro:18.04:LTS: matrix-synapse, Ubuntu:Pro:20.04:LTS: matrix-synapse, Ubuntu:Pro:22.04:LTS: matrix-synapse

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.