How severe is CVE-2021-27561?

CVE-2021-27561 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-27561 being actively exploited?

Yes. CVE-2021-27561 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2021-27561?

CVE-2021-27561 affects Yealink Device Management. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27561?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2021-27561 have an EU (EUVD) identifier?

Yes. CVE-2021-27561 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-14312. It is also flagged as exploited in the EUVD (since 2021-11-03).

When was CVE-2021-27561 published?

CVE-2021-27561 was published on 2021-10-15 and last updated on 2026-06-17.

CVE-2021-27561

CVE-2021-27561 is a critical-severity vulnerability in Yealink Device Management with a CVSS 3.x base score of 9.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2021-11-03). The underlying weakness is classified as CWE-78.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 83% (100th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2021-11-03)
EU (EUVD) id: EUVD-2021-14312
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2021-11-03)
Weakness: CWE-78
Affected product: Yealink Device Management
Published: 2021-10-15
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-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.
How severe is CVE-2021-27561?: CVE-2021-27561 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-27561 being actively exploited?: Yes. CVE-2021-27561 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-27561?: CVE-2021-27561 affects Yealink Device Management. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27561?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-27561 have an EU (EUVD) identifier?: Yes. CVE-2021-27561 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-14312. It is also flagged as exploited in the EUVD (since 2021-11-03).
When was CVE-2021-27561 published?: CVE-2021-27561 was published on 2021-10-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:yealink:device_management:*:*:*:*:*:*:*:*

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