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TI-2026-07633 Aliases CVE-2026-8686

DoS from MQTT v5.0 Deserialization Fault in core MQTT

Priority MEDIUM 44CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-125 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00388 33rd percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
FreeRTOScoreMQTT5.0.0—No fix listedCNA
  • coreMQTT VendorFreeRTOS Affected 5.0.0 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:freertos:coremqtt:5.0.0:*:*:*:*:*:*:*5.0.0VulnerableFreeRTOS
  • cpe:2.3:a:freertos:coremqtt:5.0.0:*:*:*:*:*:*:* Versions 5.0.0 Vulnerable ·FreeRTOS

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-8686
  2. 2026-10-25 EPSS moved to the below the 50th percentile

References

Patch 1

Advisory 2

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences