CVE-2021-27561
KEVYealink Device Management Server-Side Request Forgery (SSRF) Vulnerability
Description
Yealink Device Management contains a server-side request forgery (SSRF) vulnerability that allows for unauthenticated remote code execution.
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HPublishedOct 15, 2021
Last modifiedJun 17, 2026
Added to KEVNov 3, 2021
Remediation dueNov 17, 2021
References
- ssd-disclosure.com/?p=4688Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27561US Government Resource
0 recent articles mention this CVE
87
Risk assessment · Critical
Actively exploited. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1805 days
- CVSS
- 9.8 CRITICAL
- EPSS (30-day exploit probability)
- 82.9% · top 1% of all CVEs
- Weakness
- CWE-78
- Attack vector
- Network, remotely reachable
- Preconditions
- No privileges and no user interaction
Recommended actions
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.