CVE-2026-8686

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 69% 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
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.

Missing bounds validation in the MQTT v5.0 property parser in coreMQTT before 5.0.1 allows an MQTT broker to cause a denial of service by sending a crafted packet.

To remediate this issue, users should upgrade to v5.0.1.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
30.8%
KEV
Not listed

Published

May 15, 2026

Last Modified

May 19, 2026

Advisory Details (3)

Auto-updated May 18, 2026
Patch available. Sources: github.
github Patch Available

DoS from MQTT v5.0 deserialization fault in coreMQTT · Advisory · FreeRTOS/coreMQTT · GitHub

https://github.com/FreeRTOS/coreMQTT/security/advisories/GHSA-6qh9-r6jp-2wxc
generic

Release v5.0.1 · FreeRTOS/coreMQTT · GitHub

https://github.com/FreeRTOS/coreMQTT/releases/tag/v5.0.1
generic

CVE-2026-8686 - Heap out-of-bounds read in coreMQTT MQTT5 property parsing

https://aws.amazon.com/security/security-bulletins/2026-032-aws/

Vendor Advisories for CVE-2026-8686(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 10× in last 7d / 60× 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. 2026-07-06 16:27 UTCEPSS rescore
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 02:23 UTCEPSS rescore
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  5. 2026-07-05 02:31 UTCEPSS rescore
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  7. 2026-07-04 06:31 UTCEPSS rescore
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  9. 2026-07-01 15:07 UTCEPSS rescore
  10. 2026-06-30 23:22 UTCEPSS rescore
  11. 2026-06-29 21:25 UTCEG score recompute
  12. 2026-06-28 14:07 UTCEPSS rescore
  13. 2026-06-28 10:59 UTCEG score recompute
  14. 2026-06-28 04:56 UTCEPSS rescore
  15. 2026-06-27 21:48 UTCEG score recompute
  16. 2026-06-27 08:36 UTCEG score recompute
  17. 2026-06-27 03:08 UTCEPSS rescore
  18. 2026-06-26 20:08 UTCEG score recompute
  19. 2026-06-25 18:43 UTCEG score recompute
  20. 2026-06-25 13:50 UTCEPSS rescore
  21. 2026-06-24 14:05 UTCEPSS rescore
  22. 2026-06-23 21:33 UTCEPSS rescore
  23. 2026-06-22 14:25 UTCEPSS rescore
  24. 2026-06-21 14:56 UTCEPSS rescore
  25. 2026-06-21 01:59 UTCEPSS rescore
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  1. 2026-06-19 19:26 UTCEPSS rescore
  2. 2026-06-18 17:52 UTCEPSS rescore
  3. 2026-06-18 03:02 UTCEG score recompute
  4. 2026-06-17 17:53 UTCEPSS rescore
  5. 2026-06-17 13:21 UTCEG score recompute
  6. 2026-06-17 00:23 UTCEG score recompute
  7. 2026-06-16 17:53 UTCEPSS rescore
  8. 2026-06-16 11:56 UTCEG score recompute
  9. 2026-06-15 23:29 UTCEG score recompute
  10. 2026-06-15 17:49 UTCEPSS rescore
  11. 2026-06-15 17:49 UTCEPSS rescore
  12. 2026-06-15 00:10 UTCEG score recompute
  13. 2026-06-14 23:18 UTCEPSS rescore
  14. 2026-06-14 11:40 UTCEG score recompute
  15. 2026-06-13 23:12 UTCEG score recompute
  16. 2026-06-13 23:00 UTCEPSS rescore
  17. 2026-06-13 04:38 UTCEG score recompute
  18. 2026-06-12 23:12 UTCEPSS rescore
  19. 2026-06-12 23:12 UTCEPSS rescore
  20. 2026-06-12 16:10 UTCEG score recompute
  21. 2026-06-12 02:56 UTCEG score recompute
  22. 2026-06-11 14:29 UTCEG score recompute
  23. 2026-06-11 14:00 UTCEPSS rescore
  24. 2026-06-11 02:02 UTCEG score recompute
  25. 2026-06-10 22:19 UTCEPSS rescore
  26. 2026-06-10 13:35 UTCEG score recompute
  27. 2026-06-10 13:22 UTCEPSS rescore
  28. 2026-06-10 01:09 UTCEG score recompute
  29. 2026-06-09 12:42 UTCEG score recompute
  30. 2026-06-09 00:16 UTCEG score recompute
  31. 2026-06-08 14:17 UTCEPSS rescore
  32. 2026-06-08 11:49 UTCEG score recompute
  33. 2026-06-07 23:22 UTCEG score recompute
  34. 2026-06-07 15:25 UTCEPSS rescore
  35. 2026-06-07 10:55 UTCEG score recompute
  36. 2026-06-06 22:28 UTCEG score recompute
  37. 2026-06-06 13:47 UTCEPSS rescore
  38. 2026-06-06 10:01 UTCEG score recompute
  39. 2026-06-05 22:47 UTCEPSS rescore
  40. 2026-06-05 21:34 UTCEG score recompute
  41. 2026-06-05 09:07 UTCEG score recompute
  42. 2026-06-05 06:10 UTCEPSS rescore
  43. 2026-06-04 20:40 UTCEG score recompute
  44. 2026-06-04 13:12 UTCEPSS rescore
  45. 2026-06-04 08:12 UTCEG score recompute
  46. 2026-06-03 19:45 UTCEG score recompute
  47. 2026-06-03 07:18 UTCEG score recompute
  48. 2026-06-02 20:13 UTCEPSS rescore
  49. 2026-06-02 18:51 UTCEG score recompute
  50. 2026-06-02 06:24 UTCEG score recompute
  51. 2026-06-01 17:56 UTCEG score recompute
  52. 2026-06-01 13:52 UTCEPSS rescore
  53. 2026-06-01 05:29 UTCEG score recompute
  54. 2026-05-31 22:30 UTCEPSS rescore
  55. 2026-05-31 00:16 UTCEPSS rescore
  56. 2026-05-29 13:44 UTCEPSS rescore
  57. 2026-05-28 13:44 UTCEPSS rescore
  58. 2026-05-27 13:40 UTCEPSS rescore
  59. 2026-05-27 13:40 UTCEPSS rescore
  60. 2026-05-26 13:44 UTCEPSS rescore
  61. 2026-05-26 07:18 UTCEPSS rescore
  62. 2026-05-23 00:07 UTCEG score recompute
  63. 2026-05-21 22:43 UTCEPSS rescore
  64. 2026-05-20 22:38 UTCEPSS rescore
  65. 2026-05-20 12:00 UTCEG score recompute
  66. 2026-05-20 11:22 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-8686?
CVE-2026-8686 is a high vulnerability published on May 15, 2026. Missing bounds validation in the MQTT v5.0 property parser in coreMQTT before 5.0.1 allows an MQTT broker to cause a denial of service by sending a crafted packet. To remediate this issue, users should upgrade to v5.0.1.
When was CVE-2026-8686 disclosed?
CVE-2026-8686 was first published in the National Vulnerability Database on May 15, 2026, with the most recent update on May 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8686 actively exploited?
CVE-2026-8686 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 30.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-8686?
CVE-2026-8686 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-8686?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8686, 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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