CVE-2023-32323

MEDIUMNVD 5.05.0—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.0 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 67% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
5.0
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 5.0Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
5.0
EG Score
5.0(medium)
EPSS
58.1%
KEV
Not listed

Published

May 26, 2023

Last Modified

February 13, 2025

References (8)

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
matrix-synapse0.33.5 ... 1.9.1 (297 versions)1.74.0—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 50× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-11 08:26 UTCEPSS rescore
  2. 2026-07-11 08:25 UTCEPSS rescore
  3. 2026-07-09 19:08 UTCEPSS rescore
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  14. 2026-06-30 23:21 UTCEPSS rescore
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  20. 2026-06-28 04:55 UTCEPSS rescore
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  22. 2026-06-27 20:04 UTCOSV refresh
  23. 2026-06-27 03:07 UTCEPSS rescore
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  25. 2026-06-25 13:48 UTCEPSS rescore
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  1. 2026-06-25 13:48 UTCEPSS rescore
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  4. 2026-06-23 21:31 UTCEPSS rescore
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  6. 2026-06-22 14:24 UTCEPSS rescore
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  8. 2026-06-21 14:55 UTCEPSS rescore
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  10. 2026-06-21 01:58 UTCEPSS rescore
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  12. 2026-06-19 19:24 UTCEPSS rescore
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  14. 2026-06-18 17:51 UTCEPSS rescore
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  22. 2026-06-13 22:59 UTCEPSS rescore
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  24. 2026-06-12 23:10 UTCEPSS rescore
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  26. 2026-06-11 13:59 UTCEPSS rescore
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  28. 2026-06-10 22:17 UTCEPSS rescore
  29. 2026-06-10 13:21 UTCEPSS rescore
  30. 2026-06-10 06:47 UTCOSV refresh
  31. 2026-06-08 14:16 UTCEPSS rescore
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  39. 2026-06-05 06:09 UTCEPSS rescore
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  41. 2026-06-04 13:11 UTCEPSS rescore
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  43. 2026-06-02 20:12 UTCEPSS rescore
  44. 2026-06-02 20:12 UTCEPSS rescore
  45. 2026-06-02 20:12 UTCEPSS rescore
  46. 2026-06-01 13:51 UTCEPSS rescore
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  48. 2026-05-31 22:30 UTCEPSS rescore
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  51. 2026-05-31 00:15 UTCEPSS rescore
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  53. 2026-05-29 13:43 UTCEPSS rescore
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  60. 2026-05-26 07:18 UTCEPSS rescore
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  62. 2026-05-26 07:18 UTCEPSS rescore
  63. 2026-05-25 00:34 UTCEG score recompute
  64. 2026-05-24 16:52 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2023-32323?
CVE-2023-32323 is a medium vulnerability published on May 26, 2023. 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…
When was CVE-2023-32323 disclosed?
CVE-2023-32323 was first published in the National Vulnerability Database on May 26, 2023, with the most recent update on February 13, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-32323 actively exploited?
CVE-2023-32323 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 58.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2023-32323?
CVE-2023-32323 has a CVSS v3 base score of 5.0 (NVD).
How do I remediate CVE-2023-32323?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-32323, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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