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High CVSS 7.5

CVE-2025-63235

NVD analysis in progress

In sol commit 373d848 (2024-12-12), the broker does not fully release resources when handling malformed or duplicate CONNECT packets. When clients send invalid CONNECT packets - either due to repeated attempts or failed authentication - the server may silently drop the connection or send a CONNACK but fail to close the session or deallocate internal resources. This behavior allows an attacker to create numerous half-open connections that consume memory and file descriptors indefinitely, potentially triggering the Linux OOM killer and causing a denial of service.

What this means

Exposure
Exploitable remotely over the network, without authentication and with no action from the victim.
Impact
An attacker can take the service offline.
Weakness
A request that is cheap for the attacker consumes unbounded resources on the server.
Likelihood
Its EPSS score stays low: nothing points to imminent exploitation, which is no reason to leave it unpatched.

What to doFold into the next patch cycle. Start with the instances exposed to the internet.

Read automatically from the CVSS vector, the weakness type (CWE) and the EPSS score. The technical description above remains the one published by NIST.

Published
7 August 2026
CVSS
7.5 (v3.1) CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
0.32% probability of exploitation within 30 days · above 24% of all CVEs
Weakness
CWE-400
Sources
nvd
References

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