Vulnerability identifier: #VU64780

Vulnerability risk: High

CVSSv3.1: 8.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26892

CWE-ID: CWE-284

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
nats-server
Server applications / Other server solutions

Vendor: NATS - The Cloud Native Messaging System

Description

The vulnerability allows a remote attacker to execute arbitrary code on the system.

The vulnerability exists due to improper access restrictions in JWT library in NATS nats-server when handling expired credentials. A remote attacker can send a specially crafted request, gain unauthorized access and execute arbitrary code on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

nats-server: 2.0.0 - 2.1.8

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External links
http://www.openwall.com/lists/oss-security/2020/11/02/2
http://github.com/advisories/GHSA-4w5x-x539-ppf5

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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.