#VU37030 Input validation error in Synapse - CVE-2018-12423

Vulnerability identifier: #VU37030

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2018-12423

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Synapse
Server applications / Conferencing, Collaboration and VoIP solutions

Vendor: Matrix.org

Description

The vulnerability allows a remote non-authenticated attacker to manipulate data.

In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no m.room.power_levels event in force.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Synapse: 0.31.0 - 0.31.1

---

External links
https://bugs.debian.org/901549
https://github.com/matrix-org/matrix-doc/issues/1304
https://matrix.org/blog/2018/06/14/security-update-synapse-0-31-2/

---

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.