CVE-2025-56352

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-05-18. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

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

In tinyMQTT commit 6226ade15bd4f97be2d196352e64dd10937c1962 (2024-02-18), the broker mishandles protocol violations during CONNECT packet parsing. When receiving a CONNECT packet with a zero-length Client ID while CleanSession is set to 0, the broker correctly replies with a CONNACK return code 0x02 (Identifier Rejected) but fails to explicitly close the TCP connection. Since the surrounding connection teardown logic is not guaranteed to execute, each such invalid CONNECT attempt leaves the underlying socket open. Repeated attempts cause server-side resource exhaustion due to accumulating file descriptors and memory usage, potentially resulting in denial of service.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
19.7%
KEV
Not listed

Published

May 18, 2026

Last Modified

May 18, 2026

Advisory Details (2)

Auto-updated May 18, 2026
No patch confirmed yet.
generic
https://github.com/user-attachments/files/21207896/Resource_Exhaustion_Poc.txt
generic

Two bugs in tinyMQTT · Issue #19 · JustDoIt0910/tinyMQTT · GitHub

https://github.com/JustDoIt0910/tinyMQTT/issues/19

Vendor Advisories for CVE-2025-56352(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 67× 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.

Showing the most recent 100 of 178 total refreshes for this CVE.

  1. 2026-07-13 22:29 UTCEPSS rescore
  2. 2026-07-13 06:12 UTCEPSS rescore
  3. 2026-07-13 06:12 UTCEPSS rescore
  4. 2026-07-12 05:46 UTCEPSS rescore
  5. 2026-07-11 08:27 UTCEPSS rescore
  6. 2026-07-11 08:27 UTCEPSS rescore
  7. 2026-07-09 19:09 UTCEPSS rescore
  8. 2026-07-08 15:15 UTCEPSS rescore
  9. 2026-07-07 13:45 UTCEPSS rescore
  10. 2026-07-06 16:27 UTCEPSS rescore
  11. 2026-07-06 16:27 UTCEPSS rescore
  12. 2026-07-06 02:23 UTCEPSS rescore
  13. 2026-07-06 02:23 UTCEPSS rescore
  14. 2026-07-05 02:30 UTCEPSS rescore
  15. 2026-07-04 06:30 UTCEPSS rescore
  16. 2026-07-02 17:01 UTCEPSS rescore
  17. 2026-07-01 15:06 UTCEPSS rescore
  18. 2026-06-30 23:22 UTCEPSS rescore
  19. 2026-06-29 21:10 UTCEG score recompute
  20. 2026-06-29 21:10 UTCGHSA enrichment
  21. 2026-06-29 14:06 UTCEPSS rescore
  22. 2026-06-29 14:06 UTCEPSS rescore
  23. 2026-06-28 14:07 UTCEPSS rescore
  24. 2026-06-28 14:07 UTCEPSS rescore
  25. 2026-06-28 09:56 UTCEG score recompute
Show 75 more
  1. 2026-06-28 09:56 UTCGHSA enrichment
  2. 2026-06-28 04:55 UTCEPSS rescore
  3. 2026-06-27 21:23 UTCEG score recompute
  4. 2026-06-27 21:23 UTCGHSA enrichment
  5. 2026-06-27 08:26 UTCEG score recompute
  6. 2026-06-27 08:26 UTCGHSA enrichment
  7. 2026-06-27 03:08 UTCEPSS rescore
  8. 2026-06-27 03:08 UTCEPSS rescore
  9. 2026-06-26 19:56 UTCEG score recompute
  10. 2026-06-26 19:56 UTCGHSA enrichment
  11. 2026-06-25 17:46 UTCEG score recompute
  12. 2026-06-25 17:46 UTCGHSA enrichment
  13. 2026-06-25 13:49 UTCEPSS rescore
  14. 2026-06-24 14:04 UTCEPSS rescore
  15. 2026-06-24 14:04 UTCEPSS rescore
  16. 2026-06-23 21:32 UTCEPSS rescore
  17. 2026-06-22 14:25 UTCEPSS rescore
  18. 2026-06-21 14:56 UTCEPSS rescore
  19. 2026-06-21 14:56 UTCEPSS rescore
  20. 2026-06-21 01:59 UTCEPSS rescore
  21. 2026-06-21 01:59 UTCEPSS rescore
  22. 2026-06-19 19:25 UTCEPSS rescore
  23. 2026-06-19 19:25 UTCEPSS rescore
  24. 2026-06-18 17:52 UTCEPSS rescore
  25. 2026-06-18 17:52 UTCEPSS rescore
  26. 2026-06-18 02:23 UTCEG score recompute
  27. 2026-06-18 02:22 UTCGHSA enrichment
  28. 2026-06-17 17:52 UTCEPSS rescore
  29. 2026-06-17 13:15 UTCEG score recompute
  30. 2026-06-17 13:15 UTCGHSA enrichment
  31. 2026-06-17 00:19 UTCEG score recompute
  32. 2026-06-17 00:19 UTCGHSA enrichment
  33. 2026-06-16 17:52 UTCEPSS rescore
  34. 2026-06-16 17:52 UTCEPSS rescore
  35. 2026-06-16 11:44 UTCEG score recompute
  36. 2026-06-16 11:44 UTCGHSA enrichment
  37. 2026-06-15 23:12 UTCEG score recompute
  38. 2026-06-15 23:11 UTCGHSA enrichment
  39. 2026-06-15 17:48 UTCEPSS rescore
  40. 2026-06-14 23:55 UTCEG score recompute
  41. 2026-06-14 23:55 UTCGHSA enrichment
  42. 2026-06-14 23:17 UTCEPSS rescore
  43. 2026-06-14 11:24 UTCEG score recompute
  44. 2026-06-14 11:23 UTCGHSA enrichment
  45. 2026-06-13 23:00 UTCEPSS rescore
  46. 2026-06-13 22:54 UTCEG score recompute
  47. 2026-06-13 22:54 UTCGHSA enrichment
  48. 2026-06-13 04:40 UTCEG score recompute
  49. 2026-06-13 04:40 UTCGHSA enrichment
  50. 2026-06-12 23:11 UTCEPSS rescore
  51. 2026-06-12 16:10 UTCEG score recompute
  52. 2026-06-12 16:10 UTCGHSA enrichment
  53. 2026-06-12 03:41 UTCEG score recompute
  54. 2026-06-12 03:41 UTCGHSA enrichment
  55. 2026-06-11 15:11 UTCEG score recompute
  56. 2026-06-11 15:11 UTCGHSA enrichment
  57. 2026-06-11 14:00 UTCEPSS rescore
  58. 2026-06-11 14:00 UTCEPSS rescore
  59. 2026-06-11 02:40 UTCEG score recompute
  60. 2026-06-11 02:40 UTCGHSA enrichment
  61. 2026-06-10 22:18 UTCEPSS rescore
  62. 2026-06-10 22:18 UTCEPSS rescore
  63. 2026-06-10 14:11 UTCEG score recompute
  64. 2026-06-10 14:11 UTCGHSA enrichment
  65. 2026-06-10 13:22 UTCEPSS rescore
  66. 2026-06-10 13:22 UTCEPSS rescore
  67. 2026-06-10 01:41 UTCEG score recompute
  68. 2026-06-10 01:41 UTCGHSA enrichment
  69. 2026-06-09 13:12 UTCEG score recompute
  70. 2026-06-09 13:12 UTCGHSA enrichment
  71. 2026-06-09 00:43 UTCEG score recompute
  72. 2026-06-09 00:43 UTCGHSA enrichment
  73. 2026-06-08 14:16 UTCEPSS rescore
  74. 2026-06-08 14:16 UTCEPSS rescore
  75. 2026-06-08 12:13 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2025-56352?
CVE-2025-56352 is a high vulnerability published on May 18, 2026. In tinyMQTT commit 6226ade15bd4f97be2d196352e64dd10937c1962 (2024-02-18), the broker mishandles protocol violations during CONNECT packet parsing. When receiving a CONNECT packet with a zero-length Client ID while CleanSession is set to 0, the broker correctly replies with a CONNACK return code…
When was CVE-2025-56352 disclosed?
CVE-2025-56352 was first published in the National Vulnerability Database on May 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-56352 actively exploited?
CVE-2025-56352 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 19.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2025-56352?
CVE-2025-56352 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2025-56352?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-56352, 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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