Unconditionally adding an event to the epoll causes excessive CPU consumption
Priority MEDIUM 40CWE-834Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
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
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00803 56th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Eclipse Foundation | Mosquitto | up to 2.0.5 | — | No fix listed | CNA |
- Mosquitto VendorEclipse Foundation Affected up to 2.0.5 Fixed in — No fix listed CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:eclipse:mosquitto:2.0.5:*:*:*:*:*:*:* | 2.0.5 | Vulnerable | Eclipse Foundation |
- cpe:2.3:a:eclipse:mosquitto:2.0.5:*:*:*:*:*:*:* Versions 2.0.5 Vulnerable ·Eclipse Foundation
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 3 products
- Red Hat Integration Camel K 1
- Red Hat Satellite 6
- Red Hat build of Apache Camel for Spring Boot 3
Timeline
- 2026-10-02 Threatist record created from CVE-2023-5632
- 2026-10-03 Alias added: GHSA-4jhw-x435-x5f7
References
More Eclipse Foundation Mosquitto vulnerabilities
- TI-2024-09749 Eclipse Mosquito: Heap Buffer Overflow in my_subscribe_callback CVSS 4.0HIGH 7.2
- TI-2018-09002 Reachable assertion in Eclipse Mosquitto CVSS 3.0HIGH 7.5
- TI-2023-12912 The broker in Eclipse Mosquitto 1.3.2 through 2.x before 2.0.16 has a memory leak that… CVSS 3.1HIGH 7.5
- TI-2017-05287 Uncontrolled resource consumption in Eclipse Mosquitto CVSS 3.0HIGH 7.5
- TI-2018-09010 Improper authentication in Eclipse Mosquitto CVSS 3.0HIGH 8.1
- TI-2018-09009 When Eclipse Mosquitto version 1.0 to 1.5.5 (inclusive) is configured to use an ACL file… CVSS 3.0HIGH 8.1
Sources
- CVE-2023-5632 · CVE Program
- CVE-2023-5632 · NVD
- FIRST EPSS
- GHSA-4jhw-x435-x5f7 · GitHub Advisory Database · CC BY 4.0
- CVE-2023-5632 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences