#VU57555 OS Command Injection

Published: 2021-10-26 | Updated: 2021-12-26

Vulnerability identifier: #VU57555

Vulnerability risk: High

CVSSv3.1: 8.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-20837


Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Movable Type
Web applications / CMS
Movable Type Advanced
Web applications / CMS
Movable Type Premium
Web applications / CMS
Movable Type Premium Advanced
Web applications / CMS

Vendor: Six Apart Ltd


The vulnerability allows a remote attacker to execute arbitrary shell commands on the target system.

The vulnerability exists due to improper input validation in Movable Type XMLRPC API. A remote unauthenticated attacker can send a specially crafted message and execute arbitrary OS commands on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Install updates from vendor's website.

Vulnerable software versions

Movable Type: 6.8.2, r.5002

Movable Type Advanced: 6.8.2, r.5002

Movable Type Premium: 1.46

Movable Type Premium Advanced: 1.46


External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

Latest bulletins with this vulnerability