What is the CVSS score of CVE-2021-26777?

CVE-2021-26777 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 2.4%.

Is there a public PoC exploit available for CVE-2021-26777?

Yes, a public proof-of-concept exploit is available for CVE-2021-26777. Prioritise patching immediately. EPSS: 2.4%.

Compact Dc S Basic Firmware CVE-2021-26777

CRITICAL

Classic Buffer Overflow (CWE-120)

2021-12-02 cve@mitre.org

Buffer Overflow RCE Compact Dc S Basic Firmware

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

CVE Published

Dec 02, 2021 - 04:15 nvd

CRITICAL 9.8

DescriptionNVD

AnalysisAI

Buffer overflow vulnerability in function SetFirewall in index.cgi in CIRCUTOR COMPACT DC-S BASIC smart metering concentrator Firwmare version CIR_CDC_v1.2.17, allows attackers to execute arbitrary. Rated critical severity (CVSS 9.8), 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 Buffer Copy without Size Check (CWE-120), which allows attackers to overflow a buffer to corrupt adjacent memory. Buffer overflow vulnerability in function SetFirewall in index.cgi in CIRCUTOR COMPACT DC-S BASIC smart metering concentrator Firwmare version CIR_CDC_v1.2.17, allows attackers to execute arbitrary code. Affected products include: Circutor Compact Dc-S Basic Firmware.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Always validate buffer sizes before copy operations. Use bounded functions (strncpy, snprintf). Enable compiler protections.