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Vulnerabilities

Vulnerability · CVE-2021-27561

Yealink Device Management Server-Side Request Forgery (SSRF) Vulnerability

Published Mar 15, 2021 · catalog updated Jun 16, 2026 · Yealink Device Management

Patch now

CVE-2021-27561 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Yealink Device Management against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
82.86%
Remediation
Remediation guidance
Affected products
cpe yealink/device management · vendor Yealink Device Management

Yealink Device Management contains a server-side request forgery (SSRF) vulnerability that allows for unauthenticated remote code execution. VulnCheck canary evidence.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe yealink/device managementversion unspecified
  • vendor Yealink Device Managementversion unspecified

How to fix CVE-2021-27561

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-27561 is in the CISA known-exploited catalog, due Nov 17, 2021. Confirm Yealink Device Management against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply updates per vendor instructions.

What should an analyst verify?

CWE-78: OS Command Injection. EPSS 82.86%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 15, 2021 · Catalog

    Detected

    Yealink Device Management (DM) 3.6.0.20 allows command injection as root via the /sm/api/v1/firewall/zone/services URI, without authentication.

  2. Nov 3, 2021 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Nov 17, 2021 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    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

  • CISA KEVConfirmed exploitationCVE-2021-27561

    Yealink Device Management contains a server-side request forgery (SSRF) vulnerability that allows for unauthenticated remote code execution.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2021-27561

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-27561

    30-day exploitation probability 82.9%

    first.org
  • NIST NVDVulnerability recordCVE-2021-27561

    Yealink Device Management (DM) 3.6.0.20 allows command injection as root via the /sm/api/v1/firewall/zone/services URI, without authentication.

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2021-27561

    Yealink Device Management contains a server-side request forgery (SSRF) vulnerability that allows for unauthenticated remote code execution.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.