#VU51973 NULL pointer dereference in Eclipse Mosquitto - CVE-2021-28166

Vulnerability identifier: #VU51973

Vulnerability risk: Medium

CVSSv4.0: 4.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-28166

CWE-ID: CWE-476

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Eclipse Mosquitto
Server applications / Other server solutions

Vendor: Eclipse

Description

The vulnerability allows a remote user to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in Eclipse Mosquitto when processing CONNACK messages. A remote authenticated user connected with MQTT v5 can send a specially crafted CONNACK message to the broker, trigger a NULL pointer dereference error and crash the service.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Eclipse Mosquitto: 2.0.0 - 2.0.9

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External links
https://bugs.eclipse.org/bugs/show_bug.cgi?id=572608

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.