CVE-2026-8686

FAUCET Score

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.

First published: May 15, 2026Last modified: May 15, 2026

Impacted Technologies

Vendor	Product	Version(s)	CPE
		5.0.0CPE matchmatch criteria	cpe:2.3:a:freertos:coremqtt:5.0.0:::::::*

CVSS Data

CVSS version used by this source: 4.0

8.7HIGH

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

NETWORK

Attack Complexity

LOW

Attack Requirements

NONE

Privileges Required

NONE

User Interaction

NONE

VS Confidentiality

NONE

VS Integrity

NONE

VS Availability

HIGH

SS Confidentiality

NONE

SS Integrity

NONE

SS Availability

NONE

Exploit Maturity

NOT_DEFINED

CvssVersion

4.0

Exploit Intelligence

EPSS Score

0.39%

Probability of exploitation in next 30 days

EPSS Percentile

31.4%

Percentile rank of EPSS score among Peer Group

As of 2026-07-26

Model: v2026.06.15

This CVE's current EPSS score of 0.0039 is in the 8th percentile among its peer group of 36,835 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (1)

github_advisoryvendor investigatingvia nvd_reference

View patch

References

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

Vendor Advisory

github.com / FreeRTOS/coreMQTT/releases/tag/v5.0.1

Release Notes

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

Vendor Advisory