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Vulnerability record · CVE-2021-3127 · published 16 March 2021

CVE-2021-3127: Linuxfoundation nats-server vulnerability

Linuxfoundation · Nats Server

NATS Server 2.x before 2.2.0 and JWT library before 2.0.1 have Incorrect Access Control because Import Token bindings are mishandled.

7.5 CVSS 3.1 High EPSS 1.4% · top 27.6% CWE-755 · CWE-755
7.5CVSS 3.1 base score, v2 5.0
1.4%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
2References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

NATS Server 2.x before 2.2.0 and JWT library before 2.0.1 have Incorrect Access Control because Import Token bindings are mishandled.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://advisories.nats.io/CVE/CVE-2021-3127.txt ExploitVendor Advisory
https://advisories.nats.io/CVE/CVE-2021-3127.txt ExploitVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2022-28357Linuxfoundation nats-server path traversal vulnerabilityNATS nats-server 2.2.0 through 2.7.4 allows directory traversal because of an unintended path to a management action from a management account.EPSS 1.2%9.8CVE-2020-26892Linuxfoundation nats-server hard-coded credentials vulnerabilityThe JWT library in NATS nats-server before 2.1.9 has Incorrect Access Control because of how expired credentials are handled.EPSS 2.1%8.8CVE-2026-58253Linuxfoundation nats-server improper authentication vulnerabilityNATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.0, 2.12.7, and 2.11.16, when no_auth_…EPSS 0.37%8.8CVE-2022-24450Linuxfoundation nats-server missing authorization vulnerabilityNATS nats-server before 2.7.2 has Incorrect Access Control. Any authenticated user can obtain the privileges of the System account by misusing the "d…EPSS 1.3%7.5CVE-2026-58208Linuxfoundation nats-server vulnerabilityNATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, a WebSocket listener c…EPSS 0.60%7.5CVE-2026-58250Linuxfoundation nats-server null pointer dereference vulnerabilityNATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.12.8 and 2.11.17, an unauthenticated pee…EPSS 0.74%7.5CVE-2026-58210Linuxfoundation nats-server uncontrolled resource consumption vulnerabilityNATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, an unauthenticated MQT…EPSS 0.74%7.5CVE-2026-33218Linuxfoundation nats-server improper input validation vulnerabilityNATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, a client which …EPSS 0.84%

Source: NIST National Vulnerability Database (record CVE-2021-3127), CISA KEV, FIRST EPSS (scores of 2026-10-05). This page is refreshed as NVD updates the record.