Vulnerability identifier: #VU58000

Vulnerability risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-43203

CWE-ID: CWE-287

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Kotlin Ktor
Server applications / Frameworks for developing and running applications

Vendor: JetBrains s.r.o.

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to improper nonce verification during the OAuth2 authentication process. A remote attacker can bypass authentication process and gain unauthorized access to the application.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Kotlin Ktor: 1.0.0 - 1.6.3

---

External links
http://blog.jetbrains.com/blog/2021/11/08/jetbrains-security-bulletin-q3-2021

---

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.