CVE-2026-8686
CVE-2026-8686 is a high-severity vulnerability in Freertos Coremqtt with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- CVSS v4: 8.7
- EPSS exploit prediction: 0% (31st percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-30581
- Weakness: CWE-125
- Affected product: Freertos Coremqtt
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is 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. To remediate this issue, users should upgrade to v5.0.1.
- How severe is CVE-2026-8686?
- CVE-2026-8686 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2026-8686 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-8686?
- CVE-2026-8686 affects Freertos Coremqtt. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-8686?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-8686 have an EU (EUVD) identifier?
- Yes. CVE-2026-8686 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30581.
- When was CVE-2026-8686 published?
- CVE-2026-8686 was published on 2026-05-15 and last updated on 2026-06-17.
References
- https://aws.amazon.com/security/security-bulletins/2026-032-aws/
- https://github.com/FreeRTOS/coreMQTT/releases/tag/v5.0.1
- https://github.com/FreeRTOS/coreMQTT/security/advisories/GHSA-6qh9-r6jp-2wxc
Affected products (1)
- cpe:2.3:a:freertos:coremqtt:5.0.0:*:*:*:*:*:*:*
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