title: Unconditionally adding an event to the epoll causes excessive CPU consumption
description: In Eclipse Mosquito before and including 2.0.5, establishing a connection to the mosquitto server without sending data causes the EPOLLOUT event to be added, which results excessive CPU consumption. This could be used by a malicious actor to perform denial of service type attack. This issue is fixed in 2.0.6
problem types: CWE-834 Excessive Iteration
affected:
{
defaultStatus: unaffected
product: Mosquitto
programFiles: https://github.com/eclipse/mosquitto/blob/master/lib/packet_mosq.c
repo: https://github.com/eclipse/mosquitto
vendor: Eclipse
versions:
lessThanOrEqual: 2.0.5, status: affected, version: 0, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: HIGH
baseScore: 7.5
baseSeverity: HIGH
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
version: 3.1
]
format: CVSS
scenarios: GENERAL