CVE-2026-8686: FreeRTOS coreMQTT · Out-of-bounds Read
Affects FreeRTOS coreMQTTSource CVE Database V5
Not known to be exploited · CVSS 7.5 High · fixed in 5.0.1 : patch FreeRTOS coreMQTT soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 32% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.0.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| FreeRTOScoreMQTT | Affected
| Fixed in– |
GitHubfreertos/coreMQTTpkg:github/freertos/coreMQTTOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should upgrade coreMQTT to version 5.0.1 or later to remediate this vulnerability. No other mitigations are specified. The vendor advisory confirms the availability of an official fix.
Description
CVE-2026-8686 is a high-severity vulnerability in FreeRTOS coreMQTT version 5.0.0. It involves a missing bounds validation in the MQTT v5.0 property parser, which allows an MQTT broker to cause a denial of service by sending a crafted packet. The issue is fixed in version 5.0.1.