CVE-2026-8686CWE-125

DoS from MQTT v5.0 Deserialization Fault in core MQTT

High · published May 15, 2026

CVSS v4.0
8.7
EPSS
1%
Percentile
51.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.7 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
EPSS
0.00682 · 51.9th percentile
Weakness
CWE-125 · Out-of-bounds Read
Published
2026-05-15T18:38Z
EPSS history
Timeline
  • 15 MAY 18:38Z
    DoS from MQTT v5.0 Deserialization Fault in core MQTT
    cvelistv5