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Vulnerabilities

Vulnerability · CVE-2026-8686

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.

Published May 15, 2026 · catalog updated Jun 17, 2026 · Missing bounds validation in

Check if you run it

No confirmed exploitation is on record for CVE-2026-8686. EPSS is 0.68%. Act only if a listed version of Missing bounds validation in is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Missing bounds validation in).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.68%
Remediation
Advisory link
Affected products
cpe freertos/coremqtt

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe freertos/coremqtt5.0.0

How to fix CVE-2026-8686

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-8686. EPSS is 0.68%. Act only if a listed version of Missing bounds validation in is installed.

Which versions are affected?

Compare what you have installed with 5.0.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-125: Out-of-bounds Read. EPSS 0.68%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. May 15, 2026 · NIST NVD

    Detected

    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.

  2. Jun 17, 2026 · NIST NVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2026-8686

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-8686

    30-day exploitation probability 0.7%

    first.org
  • NIST NVDVulnerability recordCVE-2026-8686

    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.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.