CVE-2023-32683: Synapse is a Matrix protocol homeserver written in Python with the Twisted framework. A discovered oEmbed or image URL can bypass the…

medium5.4CVSS 3.1

AVNACLPRLUINSUCLILAN

Synapse is a Matrix protocol homeserver written in Python with the Twisted framework. A discovered oEmbed or image URL can bypass the `url_preview_url_blacklist` setting potentially allowing server side request forgery or bypassing network policies. Impact is limited to IP addresses allowed by the `url_preview_ip_range_blacklist` setting (by default this only allows public IPs) and by the limited information returned to the client: 1. For discovered oEmbed URLs, any non-JSON response or a JSON response which includes non-oEmbed information is discarded. 2. For discovered image URLs, any non-image response is discarded. Systems which have URL preview disabled (via the `url_preview_enabled` setting) or have not configured a `url_preview_url_blacklist` are not affected. This issue has been addressed in version 1.85.0. Users are advised to upgrade. User unable to upgrade may also disable URL previews.

Affected

3 ranges

Vendor	Product	Version range	Fixed in
debian	matrix-synapse	< matrix-synapse 1.90.0-1 (forky)	matrix-synapse 1.90.0-1 (forky)
matrix-org	synapse	< 1.85.0	1.85.0
matrix	synapse	< 1.85.0	1.85.0

CVSS provenance

nvdv3.15.4MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

osv5.4MEDIUM