Assessment
Why it matters
CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 82.9%; technical severity is CVSS 9.8.
Yealink Device Management (DM) 3.6.0.20 allows command injection as root via the /sm/api/v1/firewall/zone/services URI, without authentication.
Who should care
- Teams operating Device Management
- Vulnerability and exposure management teams
- Security operations teams monitoring exploitation activity
Response plan
What I would do
- Confirm whether Device Management is present in the environment.
- Identify affected versions and establish whether vulnerable services are exposed or reachable.
- Apply updates per vendor instructions.
- Review relevant security telemetry for evidence of attempted or successful exploitation.
- Document the remediation decision and track it to verified completion.
Treatment intelligence
Remediation intelligence
Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.
Verification noteAutomated link verification has not completed for this guidance yet.
Technical details
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CWE
- CWE-78
- Affected versions
- Yealink Device Management (End Including 3.6.0.20)
- Fixed versions
- No explicit fixed version is currently recorded.
- Published
- 15 October 2021
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
Signal timeline
- CVE published
- Added to CISA KEV
- Latest EPSS score: 82.9%
- Signal calculated at 83