CVE DATABASE / CVE-2021-27561
CVE-2021-27561
Yealink Device Management Server-Side Request Forgery (SSRF) Vulnerability
CVSS 9.8 · CRITICAL
⚠ CISA KEV — ACTIVELY EXPLOITED
On the CISA KEV catalog
Confirmed exploited in the wild. Added 2021-11-03.
Federal remediation due 2021-11-17.
Required action: Apply updates per vendor instructions.
Summary
Yealink Device Management (DM) 3.6.0.20 allows command injection as root via the /sm/api/v1/firewall/zone/services URI, without authentication.
CVSS 3.1 breakdown
| Base score | 9.8 (CRITICAL) |
| Vector | 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 |
Weakness type (CWE)
Affected products
Yealink device management
Check this CVE live
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References
- https://ssd-disclosure.com/?p=4688
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27561
Data: NIST NVD + CISA KEV. NVD last modified 2025-11-10. Always verify against the vendor advisory before acting.