Input validation error in Synapse - CVE-2023-32323
Published: May 24, 2023 / Updated: May 4, 2026
Vulnerability identifier: #VU129605
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2023-32323
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to improper input validation in invite_room_state handling when processing room invites. A remote user can create an oversized invite event to cause a denial of service.
Only Synapse instances with federation enabled are affected, and exploitation requires permission to create certain state events.
Affected software
Synapse
Fedora
rust-pythonize
python-matrix-common
matrix-synapse
Fedora
rust-pythonize
python-matrix-common
matrix-synapse
How to mitigate CVE-2023-32323
Install security update from vendor's website.
Synapse - update to 1.74.0
rust-pythonize - update to 0.19.0-1.fc37
python-matrix-common - update to 1.3.0-7.fc37
matrix-synapse - update to 1.80.0-5.fc37
rust-pythonize - update to 0.19.0-1.fc37
python-matrix-common - update to 1.3.0-7.fc37
matrix-synapse - update to 1.80.0-5.fc37