What’s Vulnerable › Vulnerabilities

CVE-2023-5632: Unconditionally adding an event to the epoll causes excessive CPU consumption

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-10-18 · updated 2026-06-17
• Weakness: CWE-834

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

Affected products

• The Eclipse Foundation Eclipse Mosquitto: 2.0.5

References

• https://github.com/eclipse/mosquitto/commit/18bad1ff32435e523d7507e9b2ce0010124a8f2d
• https://github.com/eclipse/mosquitto/pull/2053
• https://github.com/eclipse/mosquitto/commit/18bad1ff32435e523d7507e9b2ce0010124a8f2d
• https://github.com/eclipse/mosquitto/pull/2053

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