CVE-2025-62723 FlashMQ does not release memory of queued QoS messages
Authenticated users can cause memory exhaustion in FlashMQ by creating sessions that retain queued QoS messages, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-62723?
CVE-2025-62723 is a medium-severity denial of service vulnerability in halfgaar FlashMQ, published on 24 Oct 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
FlashMQ is a MQTT broker/server, designed for multi-CPU environments. Prior to version 1.23.2, any authenticated user can create sessions and have them collect QoS messages. When not sent to a client, these are then not released upon (eventual) session expiration. Version 1.23.2 fixes the issue.
Weakness: CWE-772
Which versions are affected by CVE-2025-62723?
It affects 1 product.
Products include Flashmq Flashmq.
How do I fix CVE-2025-62723?
No fix has been published for CVE-2025-62723 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-62723 being exploited?
There is no known exploitation of CVE-2025-62723 in the wild and no public exploit code.
Other vulnerabilities in halfgaar FlashMQ
Sources
Also known as GHSA-7mhp-22q4-r6vv.