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Vulnerability · Published May 26, 2023 · Assigned by GitHub_M

CVE-2023-32323Synapse Outgoing federation to specific hosts can be disabled by sending malicious invites

Medium 5.0

In plain English

A medium-severity improper input validation in synapse from matrix-org. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 62% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.0Medium
Exploit odds (30 days)1.0%top 37.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. A malicious user on a Synapse homeserver X with permission to create certain state events can disable outbound federation from X to an arbitrary homeserver Y. Synapse instances with federation disabled are not affected. In versions of Synapse up to and including 1.73, Synapse did not limit the size of `invite_room_state`, meaning that it was possible to create an arbitrarily large invite event. Synapse 1.74 refuses to create oversized `invite_room_state` fields. Server operators should upgrade to Synapse 1.74 or newer urgently.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20synapse1.74.0-r0ALPINE-CVE-2023-32323
Alpine:v3.21synapse1.74.0-r0ALPINE-CVE-2023-32323
Alpine:v3.22synapse1.74.0-r0ALPINE-CVE-2023-32323
Alpine:v3.23synapse1.74.0-r0ALPINE-CVE-2023-32323
Alpine:v3.24synapse1.74.0-r0ALPINE-CVE-2023-32323
Debian:14matrix-synapse1.74.0-1DEBIAN-CVE-2023-32323
PyPImatrix-synapse1.74.0GHSA-f3wc-3vxv-xmvr
PyPImatrix-synapse1.74.0PYSEC-2023-67
Ubuntu:22.04:LTSmatrix-synapseno fix listedUBUNTU-CVE-2023-32323

Affected products (as reported)

VendorProductVersions
matrix-org synapse < 1.74.0

Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L

References