CVE-2021-27561
CriticalPublished
Yealink Device Management Server-Side Request Forgery (SSRF) Vulnerability
- Published
- Oct 15, 2021
- Updated
- Oct 21, 2025
- Assigning CNA
- mitre
- Evidence observed
- Nov 3, 2021
Primary CVSS
9.8/ 10Critical
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H82.9%
High · next 30 days
- Percentile
- 99.7%
- Model date
- Oct 18, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
CISA Known Exploited
This CVE appears in the CISA Known Exploited Vulnerabilities catalog.
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.
Sources
Repository evidence: Files: 1 · Repositories: 1
1 Template
http/cves/2021/CVE-2021-27561.yaml
Nuclei TemplatesDeclared conditions
- network: http($.protocol_keys)
- verification: status,word($.matchers[*].type)
Responsible use
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