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 68% 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
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 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)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
33%
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 7× in last 7d / 30× 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 146 total refreshes for this CVE.

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

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 0% probability of exploitation in the next 30 days, which ranks it in the top 67.3% of all scored CVEs.
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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