PatchTheCVECVE-2021-33032: A Remote Code Execution (RCE) vulnerability in the WebUI component of the eQ-3 HomeMatic CCU2 firmware up to a
CVE-2021-33032 is a critical-severity flaw (CVSS 10.0) affecting homematic ccu2 firmware, homematic ccu3 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
A Remote Code Execution (RCE) vulnerability in the WebUI component of the eQ-3 HomeMatic CCU2 firmware up to and including version 2.57.5 and CCU3 firmware up to and including version 3.57.5 allows remote unauthenticated attackers to execute system commands as root via a simple HTTP request.
Why this priority
- Critical severity
- EPSS top 1%: very likely to be exploited
- Public exploit reference
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 10.0 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 52.2% (top 1%) |
| CISA exploited list | No |
| Weakness | CWE-78 |
| Published | 2021-07-22 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- Write-up: novag.github.io/posts/homematic-unauthenticated-remote-code-execution/
- Write-up: www.eq-3.de/downloads/software/HM-CCU2-Firmware_Updates/HM-CCU-2.59.7/HM-CCU2-Changelog.2.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-33032?
homematic ccu2 firmware: upgrade to newer than 2.57.5; homematic ccu3 firmware: upgrade to newer than 3.57.5. Exact commands for each OS are on this page.
Is CVE-2021-33032 being exploited?
CVE-2021-33032 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-33032 affect?
CVE-2021-33032 affects homematic ccu2 firmware, homematic ccu3 firmware. Severity is critical (CVSS 10.0). A Remote Code Execution (RCE) vulnerability in the WebUI component of the eQ-3 HomeMatic CCU2 firmware up to and including version 2.57.5 and CCU3 firmware up to and including version 3.57.5 allows remote unauthenticated attackers to execut
How urgent is CVE-2021-33032?
Priority 70/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action
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