CVE-2023-45129

MEDIUMNVD 4.94.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.9 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 50% 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
4.9
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 4.9Exploit: 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. Prior to version 1.94.0, a malicious server ACL event can impact performance temporarily or permanently leading to a persistent denial of service. Homeservers running on a closed federation (which presumably do not need to use server ACLs) are not affected. Server administrators are advised to upgrade to Synapse 1.94.0 or later. As a workaround, rooms with malicious server ACL events can be purged and blocked using the admin API.

CVSS v3
4.9
EG Score
4.9(medium)
EPSS
63.6%
KEV
Not listed

Published

October 10, 2023

Last Modified

June 17, 2026

References (14)

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
matrix-synapse0.33.5 ... 1.94.0rc1 (351 versions)1.94.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 47× 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 08:26 UTCEPSS rescore
  3. 2026-07-09 19:08 UTCEPSS rescore
  4. 2026-07-08 15:13 UTCEPSS rescore
  5. 2026-07-07 13:44 UTCEPSS rescore
  6. 2026-07-06 16:26 UTCEPSS rescore
  7. 2026-07-06 16:26 UTCEPSS rescore
  8. 2026-07-06 02:22 UTCEPSS rescore
  9. 2026-07-05 02:29 UTCEPSS rescore
  10. 2026-07-04 06:29 UTCEPSS rescore
  11. 2026-07-01 15:05 UTCEPSS rescore
  12. 2026-06-30 23:21 UTCEPSS rescore
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  14. 2026-06-29 14:05 UTCEPSS rescore
  15. 2026-06-28 14:06 UTCEPSS rescore
  16. 2026-06-28 14:06 UTCEPSS rescore
  17. 2026-06-28 04:55 UTCEPSS rescore
  18. 2026-06-28 04:55 UTCEPSS rescore
  19. 2026-06-27 08:04 UTCOSV refresh
  20. 2026-06-27 03:07 UTCEPSS rescore
  21. 2026-06-27 03:07 UTCEPSS rescore
  22. 2026-06-25 13:48 UTCEPSS rescore
  23. 2026-06-25 13:48 UTCEPSS rescore
  24. 2026-06-24 14:04 UTCEPSS rescore
  25. 2026-06-24 14:04 UTCEPSS rescore
Show 61 more
  1. 2026-06-23 21:31 UTCEPSS rescore
  2. 2026-06-23 21:31 UTCEPSS rescore
  3. 2026-06-22 14:24 UTCEPSS rescore
  4. 2026-06-22 14:24 UTCEPSS rescore
  5. 2026-06-21 14:55 UTCEPSS rescore
  6. 2026-06-21 14:55 UTCEPSS rescore
  7. 2026-06-21 01:58 UTCEPSS rescore
  8. 2026-06-21 01:58 UTCEPSS rescore
  9. 2026-06-19 19:24 UTCEPSS rescore
  10. 2026-06-19 19:24 UTCEPSS rescore
  11. 2026-06-18 17:51 UTCEPSS rescore
  12. 2026-06-17 17:51 UTCEPSS rescore
  13. 2026-06-17 17:51 UTCEPSS rescore
  14. 2026-06-16 17:51 UTCEPSS rescore
  15. 2026-06-16 17:51 UTCEPSS rescore
  16. 2026-06-15 17:47 UTCEPSS rescore
  17. 2026-06-15 17:47 UTCEPSS rescore
  18. 2026-06-14 23:16 UTCEPSS rescore
  19. 2026-06-13 22:59 UTCEPSS rescore
  20. 2026-06-13 22:59 UTCEPSS rescore
  21. 2026-06-12 23:10 UTCEPSS rescore
  22. 2026-06-12 23:10 UTCEPSS rescore
  23. 2026-06-11 13:59 UTCEPSS rescore
  24. 2026-06-11 13:59 UTCEPSS rescore
  25. 2026-06-10 22:17 UTCEPSS rescore
  26. 2026-06-10 13:21 UTCEPSS rescore
  27. 2026-06-10 13:21 UTCEPSS rescore
  28. 2026-06-09 18:17 UTCOSV refresh
  29. 2026-06-08 14:16 UTCEPSS rescore
  30. 2026-06-08 14:16 UTCEPSS rescore
  31. 2026-06-07 15:23 UTCEPSS rescore
  32. 2026-06-07 15:23 UTCEPSS rescore
  33. 2026-06-06 13:46 UTCEPSS rescore
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  35. 2026-06-05 22:46 UTCEPSS rescore
  36. 2026-06-05 22:46 UTCEPSS rescore
  37. 2026-06-05 06:09 UTCEPSS rescore
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  39. 2026-06-05 06:09 UTCEPSS rescore
  40. 2026-06-04 13:11 UTCEPSS rescore
  41. 2026-06-04 13:11 UTCEPSS rescore
  42. 2026-06-02 20:12 UTCEPSS rescore
  43. 2026-06-02 20:12 UTCEPSS rescore
  44. 2026-06-01 13:51 UTCEPSS rescore
  45. 2026-06-01 13:51 UTCEPSS rescore
  46. 2026-05-31 22:30 UTCEPSS rescore
  47. 2026-05-31 22:29 UTCEPSS rescore
  48. 2026-05-31 00:15 UTCEPSS rescore
  49. 2026-05-31 00:15 UTCEPSS rescore
  50. 2026-05-29 13:43 UTCEPSS rescore
  51. 2026-05-29 13:43 UTCEPSS rescore
  52. 2026-05-28 13:44 UTCEPSS rescore
  53. 2026-05-28 13:43 UTCEPSS rescore
  54. 2026-05-27 13:39 UTCEPSS rescore
  55. 2026-05-27 13:39 UTCEPSS rescore
  56. 2026-05-26 13:43 UTCEPSS rescore
  57. 2026-05-26 13:43 UTCEPSS rescore
  58. 2026-05-26 07:18 UTCEPSS rescore
  59. 2026-05-26 07:18 UTCEPSS rescore
  60. 2026-05-26 07:18 UTCEPSS rescore
  61. 2026-05-24 16:06 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2023-45129?
CVE-2023-45129 is a medium vulnerability published on October 10, 2023. Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Prior to version 1.94.0, a malicious server ACL event can impact performance temporarily or permanently leading to a persistent denial of service. Homeservers running on a closed federation (which…
When was CVE-2023-45129 disclosed?
CVE-2023-45129 was first published in the National Vulnerability Database on October 10, 2023, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-45129 actively exploited?
CVE-2023-45129 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 63.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2023-45129?
CVE-2023-45129 has a CVSS v3 base score of 4.9 (NVD).
How do I remediate CVE-2023-45129?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-45129, 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.

Dependency Blast Radius

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