CVE-2026-36590: An issue in EMQ NanoMQ v.0.24.9 allows a remote attacker to cause a denial of service via the nni_qos_db_set f

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HIGH 7.5REMOTEDOWNGRADE

CVE-2026-36590 is a high-severity flaw (CVSS 7.5) affecting nanomq. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue in EMQ NanoMQ v.0.24.9 allows a remote attacker to cause a denial of service via the nni_qos_db_set function in broker_tcp.c component

Why this priority

High severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 53%)
CISA exploited list	No
Weakness	CWE-400, CWE-772
Published	2026-07-15
Last modified	2026-10-24

Publisher (CNA): MITRE · Vendor: emqx

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-15 22:16 UTCPublished CVE record published
2026-10-24 21:10 UTCUpdated Record last modified

emqx nanomq DOWNGRADE

Affected: 0.24.9

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.24.9

1. Check installed version

apt-cache policy nanomq || rpm -q nanomq || nanomq --version

2. No fixed release: DOWNGRADE to a release before 0.24.9 (Debian / Ubuntu)

apt-cache madison nanomq sudo apt install nanomq=<VERSION_BEFORE_0.24.9> sudo apt-mark hold nanomq

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list nanomq sudo dnf downgrade nanomq-<VERSION_BEFORE_0.24.9> sudo dnf versionlock add nanomq

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-36590?

nanomq: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-36590 being exploited?

CVE-2026-36590 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-36590 affect?

CVE-2026-36590 affects nanomq. Severity is high (CVSS 7.5). An issue in EMQ NanoMQ v.0.24.9 allows a remote attacker to cause a denial of service via the nni_qos_db_set function in broker_tcp.c component

How urgent is CVE-2026-36590?

Priority 43/100. High severity; Remotely exploitable, no login, no user action

References

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