7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
0.001 Low
EPSS
Percentile
47.6%
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.
If your NATS servers do not trust any accounts which are managed by untrusted entities, then malformed User credentials are unlikely to be encountered.
Upgrade the JWT dependency in any application using it.
Upgrade the NATS server if using NATS Accounts.
CPE | Name | Operator | Version |
---|---|---|---|
github.com/nats-io/nats-server/v2 | lt | 2.1.9 | |
github.com/nats-io/jwt | lt | 1.1.0 |
www.openwall.com/lists/oss-security/2020/11/02/2
advisories.nats.io/CVE/CVE-2020-26521.txt
github.com/nats-io/jwt/pull/107
github.com/nats-io/jwt/security/advisories/GHSA-h2fg-54x9-5qhq
github.com/nats-io/nats-server/commit/9ff8bcde2e46009e98bd9e88f598af355f62c168
github.com/nats-io/nats-server/commits/master
lists.fedoraproject.org/archives/list/[email protected]/message/VT67XCLIIBYRT762SVFBYFFTQFVSM3SI
nvd.nist.gov/vuln/detail/CVE-2020-26521
pkg.go.dev/vuln/GO-2022-0402
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
0.001 Low
EPSS
Percentile
47.6%