SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2021-27561

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

KEVCRITICAL 9.8EPSS 82.9%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 November 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

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.

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
82.86% probability · 100th percentile
CISA KEV
Listed 3 November 2021 · due 17 November 2021
Weakness
CWE-78
Affected
yealink/device management
Source
cve@mitre.org

CISA notes

Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2021-27561

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.