CVE-2021-27561 is a vulnerability in Yealink Device Management
Published on October 15, 2021
Yealink Device Management (DM) 3.6.0.20 allows command injection as root via the /sm/api/v1/firewall/zone/services URI, without authentication.
Known Exploited Vulnerability
This Yealink Device Management Server Pre-Authorization SSRF vulnerability is part of CISA's list of Known Exploited Vulnerabilities. Yealink Device Management (DM) 3.6.0.20 allows command injection as root via the /sm/api/v1/firewall/zone/services URI, without authentication.
The following remediation steps are recommended / required by November 17, 2021: Apply updates per vendor instructions.
Vulnerability Analysis
CVE-2021-27561 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. This vulnerability is known to be actively exploited by threat actors in an automatable fashion. The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.
Weakness Type
What is a Shell injection Vulnerability?
The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.
CVE-2021-27561 has been classified to as a Shell injection vulnerability or weakness.
Products Associated with CVE-2021-27561
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Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.