How severe is CVE-2020-12834?

CVE-2020-12834 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-12834 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 11% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-12834?

CVE-2020-12834 primarily affects Eq-3 Homematic Ccu2 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-12834?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-12834 published?

CVE-2020-12834 was published on 2020-05-15 and last updated on 2026-06-17.

CVE-2020-12834

CVE-2020-12834 is a critical-severity vulnerability in Eq-3 Homematic Ccu2 Firmware with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 11% places it in the 95th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-276.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 11% (95th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-276
Affected product: Eq-3 Homematic Ccu2 Firmware
Published: 2020-05-15
Last modified: 2026-06-17

Description

eQ-3 Homematic Central Control Unit (CCU)2 through 2.51.6 and CCU3 through 3.51.6 allow Remote Code Execution in the JSON API Method ReGa.runScript, by unauthenticated attackers with access to the web interface, due to the default auto-login feature being enabled during first-time setup (or factory reset).

Frequently asked questions

What is CVE-2020-12834?: eQ-3 Homematic Central Control Unit (CCU)2 through 2.51.6 and CCU3 through 3.51.6 allow Remote Code Execution in the JSON API Method ReGa.runScript, by unauthenticated attackers with access to the web interface, due to the default auto-login feature being enabled during first-time setup (or factory reset).
How severe is CVE-2020-12834?: CVE-2020-12834 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-12834 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 11% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-12834?: CVE-2020-12834 primarily affects Eq-3 Homematic Ccu2 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-12834?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-12834 published?: CVE-2020-12834 was published on 2020-05-15 and last updated on 2026-06-17.

References

https://psytester.github.io/CVE-2020-12834/

Affected products (2)

cpe:2.3:o:eq-3:homematic_ccu2_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:eq-3:ccu3_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Eq-3 Homematic Ccu2 Firmware

CVE-2021-33032 — Critical (CVSS 10.0): A Remote Code Execution (RCE) vulnerability in the WebUI component of the eQ-3 HomeMatic CCU2 firmware up to and…
CVE-2019-18939 — Critical (CVSS 9.8): eQ-3 Homematic CCU2 2.47.20 and CCU3 3.47.18 with the HM-Print AddOn through 1.2a installed allow Remote Code Execution…
CVE-2019-18938 — Critical (CVSS 9.8): eQ-3 Homematic CCU2 2.47.20 and CCU3 3.47.18 with the E-Mail AddOn through 1.6.8.c installed allow Remote Code…
CVE-2019-18937 — Critical (CVSS 9.8): eQ-3 Homematic CCU2 2.47.20 and CCU3 3.47.18 with the Script Parser AddOn through 1.8 installed allow Remote Code…
CVE-2019-16199 — Critical (CVSS 9.8): eQ-3 Homematic CCU2 before 2.47.18 and CCU3 before 3.47.18 allow Remote Code Execution by unauthenticated attackers…
CVE-2019-9585 — Critical (CVSS 9.8): eQ-3 Homematic CCU2 prior to 2.47.10 and CCU3 prior to 3.47.10 JSON API has Improper Access Control for…

All CVEs affecting Eq-3 Homematic Ccu2 Firmware →

Other CWE-276 (Incorrect Default Permissions) vulnerabilities

CVE-2022-42150 — Critical (CVSS 10.0): TinyLab linux-lab v1.1-rc1 and cloud-labv0.8-rc2, v1.1-rc1 are vulnerable to insecure permissions. The default…
CVE-2020-29492 — Critical (CVSS 10.0): Dell Wyse ThinOS 8.6 and prior versions contain an insecure default configuration vulnerability. A remote…
CVE-2020-29491 — Critical (CVSS 10.0): Dell Wyse ThinOS 8.6 and prior versions contain an insecure default configuration vulnerability. A remote…
CVE-2025-40585 — Critical (CVSS 9.9): A vulnerability has been identified in Energy Services (All versions with G5DFR). Affected solutions using G5DFR…
CVE-2019-19896 — Critical (CVSS 9.9): In IXP EasyInstall 6.2.13723, there is Remote Code Execution via weak permissions on the Engine Service share. The…
CVE-2020-37129 — Critical (CVSS 9.8): Memu Play 7.1.3 contains an insecure folder permissions vulnerability that allows low-privileged users to modify the…

Browse all CWE-276 (Incorrect Default Permissions) vulnerabilities →