HOMEVULNERABILITIESCVE-2023-32323
MEDIUM

CVE-2023-32323

CWE-20Published: May 26, 2023· Updated: Jun 17, 2026

4.3
CVSS v3.1

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.

NVD Source

Technical Analysis

CVE-2023-32323 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityLow
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Affected Vendors & Products

matrix1 product(s)
synapse
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/matrix-org/synapse/pull/14642
PATCHhttps://github.com/matrix-org/synapse/pull/14642
ADVISORYhttps://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr
ADVISORYhttps://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr

All References (8)

→
https://github.com/matrix-org/synapse/issues/14492Exploit · Issue Tracking
→
https://github.com/matrix-org/synapse/pull/14642Patch
→
https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvrMitigation · Vendor Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/
→
https://github.com/matrix-org/synapse/issues/14492Exploit · Issue Tracking
→
https://github.com/matrix-org/synapse/pull/14642Patch
→
https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvrMitigation · Vendor Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/

Quick Facts

CVE IDCVE-2023-32323
CVSS Score4.3 / 10
SeverityMEDIUM
WeaknessCWE-20
CISA KEVNo
Affected1 vendor(s)
PublishedMay 26, 2023

Related CVEs (CWE-20)

CVE-2026-48281
10.0
CVE-2026-48316
10.0
CVE-2011-4755
10.0
CVE-2026-33587
10.0
CVE-2026-48277
10.0
CVE-2026-47928
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2023-32323 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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