Multiple vulnerabilities in nats-server

Published: 2020-11-06 | Updated: 2022-06-29

Risk	High
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2020-26892 CVE-2020-26521
CWE-ID	CWE-284 CWE-476
Exploitation vector	Network
Public exploit	N/A
Vulnerable software Subscribe	nats-server Server applications / Other server solutions
Vendor	NATS - The Cloud Native Messaging System

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Improper access control

EUVDB-ID: #VU64780

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 - Improper Access Control

Exploit availability: No

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

External links

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

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.

2) NULL pointer dereference

EUVDB-ID: #VU64778

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-26521

CWE-ID: CWE-476 - NULL Pointer Dereference