MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLWhtbTktcjJtMi1xZzl3

High

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Nil dereference in NATS JWT causing DoS of nats-server

Affected Packages	Affected Versions	Fixed Versions
go:github.com/nats-io/jwt	< 1.1.0	1.1.0
543 Dependent packages 25,517 Dependent repositories Affected Version Ranges All affected versions 0.0.3, 0.0.4, 0.0.5, 0.0.6, 0.0.8, 0.1.0, 0.2.0, 0.2.2, 0.2.4, 0.2.6, 0.2.8, 0.2.10, 0.2.12, 0.2.14, 0.2.16, 0.3.0, 0.3.2, 1.0.0, 1.0.1 All unaffected versions 1.1.0, 1.1.1, 1.2.0, 1.2.1, 1.2.2, 2.4.0, 2.4.1, 2.5.0, 2.5.2, 2.5.3, 2.5.4, 2.5.5, 2.5.6, 2.5.7, 2.5.8, 2.6.0, 2.7.0, 2.7.2, 2.7.3
go:github.com/nats-io/nats-server/v2	< 2.1.9	2.1.9
6,417 Dependent packages 24,884 Dependent repositories Affected Version Ranges All affected versions 2.0.0, 2.0.2, 2.0.4, 2.1.0, 2.1.2, 2.1.4, 2.1.6, 2.1.7, 2.1.8 All unaffected versions 2.1.9, 2.2.0, 2.2.1, 2.2.2, 2.2.3, 2.2.4, 2.2.5, 2.2.6, 2.3.0, 2.3.1, 2.3.2, 2.3.3, 2.3.4, 2.4.0, 2.5.0, 2.6.0, 2.6.1, 2.6.2, 2.6.3, 2.6.4, 2.6.5, 2.6.6, 2.7.0, 2.7.1, 2.7.2, 2.7.3, 2.7.4, 2.8.0, 2.8.1, 2.8.2, 2.8.3, 2.8.4, 2.9.0, 2.9.1, 2.9.2, 2.9.3, 2.9.4, 2.9.5, 2.9.6, 2.9.7, 2.9.8, 2.9.9, 2.9.10, 2.9.11, 2.9.12, 2.9.14, 2.9.15, 2.9.16, 2.9.17, 2.9.18, 2.9.19, 2.9.20, 2.9.21, 2.9.22, 2.9.23, 2.9.24, 2.9.25, 2.10.0, 2.10.1, 2.10.2, 2.10.3, 2.10.4, 2.10.5, 2.10.6, 2.10.7, 2.10.8, 2.10.9, 2.10.10, 2.10.11, 2.10.12, 2.10.14, 2.10.15, 2.10.16, 2.10.17, 2.10.18, 2.10.19, 2.10.20, 2.10.21, 2.10.22, 2.10.23, 2.10.24, 2.10.25, 2.10.26, 2.10.27, 2.10.28, 2.10.29, 2.11.0, 2.11.1, 2.11.2, 2.11.3, 2.11.4, 2.11.5, 2.11.6

(This advisory is canonically https://advisories.nats.io/CVE/CVE-2020-26521.txt)

Problem Description

The NATS account system has an Operator trusted by the servers, which signs Accounts, and each Account can then create and sign Users within their account. The Operator should be able to safely issue Accounts to other entities which it does not fully trust.

A malicious Account could create and sign a User JWT with a state not created by the normal tooling, such that decoding by the NATS JWT library (written in Go) would attempt a nil dereference, aborting execution.

The NATS Server is known to be impacted by this.

Affected versions

JWT library

all versions prior to 1.1.0

NATS Server

Version 2 prior to 2.1.9

Impact

JWT library

Programs would nil dereference and panic, aborting execution by default.

NATS server

Denial of Service caused by process termination

Workaround

If your NATS servers do not trust any accounts which are managed by untrusted entities, then malformed User credentials are unlikely to be encountered.

Solution

Upgrade the JWT dependency in any application using it.

Upgrade the NATS server if using NATS Accounts.

References:

ecosyste.ms

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Advisories

MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLWhtbTktcjJtMi1xZzl3

Nil dereference in NATS JWT causing DoS of nats-server

Affected Version Ranges

All affected versions

All unaffected versions

Affected Version Ranges

All affected versions

All unaffected versions

Problem Description

Affected versions

JWT library

NATS Server

Impact

JWT library

NATS server

Workaround

Solution

Identifiers

Risk

Severity

Classification

Source

Origin

Repository

Date and time

Published

Updated

API