PYSEC-2021-425: matrix-synapse fixed in cb35df940a828bc40b96daed997b5ad4c7842fd3 and 1.41.1

PYSEC-2021-425 PUBLISHED

Record from OSV · Published August 31, 2021

matrix-synapse is fixed in cb35df940a828bc40b96daed997b5ad4c7842fd3 and 1.41.1 (PyPI)

Matrix is an ecosystem for open federated Instant Messaging and Voice over IP. In versions 1.41.0 and prior, unauthorised users can access the membership (list of members, with their display names) of a room if they know the ID of the room. The vulnerability is limited to rooms with `shared` history visibility. Furthermore, the unauthorised user must be using an account on a vulnerable homeserver that is in the room. Server administrators should upgrade to 1.41.1 or later in order to receive the patch. One workaround is available. Administrators of servers that use a reverse proxy could, with potentially unacceptable loss of functionality, block the endpoints: `/_matrix/client/r0/rooms/{room_id}/members` with `at` query parameter, and `/_matrix/client/unstable/rooms/{room_id}/members` with `at` query parameter.

Fixed versions

Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.

Package	Ecosystem	Fixed in
matrix-synapse	PyPI	cb35df940a828bc40b96daed997b5ad4c7842fd3, 1.41.1

Affected products

Vendor	Product	Versions
PyPI	matrix-synapse	0, 0, 0.33.5.1

Timeline

Aug 31, 2021 CVE Published
Feb 26, 2026 CVE Updated

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The same record, from the CLI:

vulnetix vdb vuln PYSEC-2021-425
vulnetix vdb fixes PYSEC-2021-425

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  "https://api.vdb.vulnetix.com/v2/vuln/PYSEC-2021-425/fixes/registry"

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References

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