What is the CVSS score of CVE-2021-27954?

CVE-2021-27954 has a CVSS 3.1 base score of 8.2 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H. EPSS exploitation probability: 0.9%.

Is there a public PoC exploit available for CVE-2021-27954?

Yes, a public proof-of-concept exploit is available for CVE-2021-27954. Prioritise patching immediately. EPSS: 0.9%.

Ecobee3 Lite Firmware CVE-2021-27954

HIGH

Out-of-bounds Write (CWE-787)

2021-08-03 cve@mitre.org

Buffer Overflow Denial Of Service Memory Corruption Ecobee3 Lite Firmware

8.2

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

8.2 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

High

Lifecycle Timeline

CVE Published

Aug 03, 2021 - 15:15 nvd

HIGH 8.2

DescriptionNVD

A heap-based buffer overflow vulnerability exists on the ecobee3 lite 4.5.81.200 device in the HKProcessConfig function of the HomeKit Wireless Access Control setup process. A threat actor can exploit this vulnerability to force the device to connect to a SSID or cause a denial of service.

AnalysisAI

A heap-based buffer overflow vulnerability exists on the ecobee3 lite 4.5.81.200 device in the HKProcessConfig function of the HomeKit Wireless Access Control setup process. Rated high severity (CVSS 8.2), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Out-of-bounds Write (CWE-787), which allows attackers to write data beyond allocated buffer boundaries leading to code execution or crashes. A heap-based buffer overflow vulnerability exists on the ecobee3 lite 4.5.81.200 device in the HKProcessConfig function of the HomeKit Wireless Access Control setup process. A threat actor can exploit this vulnerability to force the device to connect to a SSID or cause a denial of service. Affected products include: Ecobee Ecobee3 Lite Firmware.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate write boundaries, use memory-safe languages, enable compiler protections (ASLR, stack canaries).