CVE-2021-27561

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

As of , CVE-2021-27561 in Yealink Device Management is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.

Exploited
Yes: CISA listed it on 3 November 2021
US federal deadline
17 November 202114 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.83Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
EPSS when listed
Not availableCISA listed it before 4 February 2022, where the EPSS files we read begin.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
No vendor link in CISA's entry

What CISA says to do

Apply updates per vendor instructions.

CISA's required action

What the flaw is

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

CISA's 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.

The CVE record's description, from mitre

CVE published
15 October 2021
Assigned by
mitre
CVSS
9.8 Critical (CVSS 3.1, from CISA-ADP)
CWE-78
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CISA SSVC, exploitation
active
CISA SSVC, automatable
yes
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

Read further