CVE-2021-27952
CVE-2021-27952 is a critical-severity vulnerability in Ecobee Ecobee3 Lite Firmware with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-798.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- CVSS v2: 5.0
- EPSS exploit prediction: 1% (62nd percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-798
- Affected product: Ecobee Ecobee3 Lite Firmware
- Published:
- Last modified:
Description
Hardcoded default root credentials exist on the ecobee3 lite 4.5.81.200 device. This allows a threat actor to gain access to the password-protected bootloader environment through the serial console.
Frequently asked questions
- What is CVE-2021-27952?
- Hardcoded default root credentials exist on the ecobee3 lite 4.5.81.200 device. This allows a threat actor to gain access to the password-protected bootloader environment through the serial console.
- How severe is CVE-2021-27952?
- CVE-2021-27952 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-2021-27952 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-27952?
- CVE-2021-27952 affects Ecobee Ecobee3 Lite Firmware. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2021-27952?
- 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-2021-27952 published?
- CVE-2021-27952 was published on 2021-08-03 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:o:ecobee:ecobee3_lite_firmware:4.5.81.200:*:*:*:*:*:*:*
More vulnerabilities in Ecobee Ecobee3 Lite Firmware
- CVE-2021-27954 — High (CVSS 8.2): A heap-based buffer overflow vulnerability exists on the ecobee3 lite 4.5.81.200 device in the HKProcessConfig function…
- CVE-2021-27953 — High (CVSS 7.5): A NULL pointer dereference vulnerability exists on the ecobee3 lite 4.5.81.200 device in the HomeKit Wireless Access…
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