# CVE-2021-3127: GO-2022-0386 - Import token permissions checking not enforced in github.com/nats-io/jwt

Source: https://junglewise.ai/threats/cve-2021-3127-nats-io-jwt-not-enforcing-checking-of-import-token-permissions  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2022-07-01  
License: CC BY 4.0 with a link back

CVE-2021-3127 · Severity: low · CVSS 3.1 · Published 2022-07-01

Import token permissions checking not enforced in github.com/nats-io/jwt

Technologies: [github.com/nats-io/jwt (Go)](https://junglewise.ai/threats/technologies/github-com-nats-io-jwt), [github.com/nats-io/nats-server/v2 (Go)](https://junglewise.ai/threats/technologies/github-com-nats-io-nats-server-v2). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2021-3127 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2021-3127 being exploited in the wild.

**How severe is CVE-2021-3127?** Low severity, with a CVSS score of 3.1, published 1 July 2022.

**Which products and versions are affected?** github.com/nats-io/jwt (Go) SEMVER:introduced=0,fixed=1.2.3-0.20210314221642-a826c77dc9d2, SEMVER:introduced=0,last_affected=1.2.2; github.com/nats-io/jwt/v2 (Go) SEMVER:introduced=0,fixed=2.0.1; github.com/nats-io/nats-server/v2 (Go) SEMVER:introduced=0,fixed=2.2.0.

**Is there a fix for CVE-2021-3127?** Yes. github.com/nats-io/jwt (Go): upgrade to 1.2.3-0.20210314221642-a826c77dc9d2 or later; github.com/nats-io/jwt/v2 (Go): upgrade to 2.0.1 or later; github.com/nats-io/nats-server/v2 (Go): upgrade to 2.2.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2021-3127?** Check whether you run github.com/nats-io/jwt (Go), github.com/nats-io/jwt/v2 (Go) or github.com/nats-io/nats-server/v2 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/nats-io/jwt (Go): upgrade to 1.2.3-0.20210314221642-a826c77dc9d2 or later

  ```sh
  go get github.com/nats-io/jwt@v1.2.3-0.20210314221642-a826c77dc9d2
  ```

- github.com/nats-io/jwt/v2 (Go): upgrade to 2.0.1 or later

  ```sh
  go get github.com/nats-io/jwt/v2@v2.0.1
  ```

- github.com/nats-io/nats-server/v2 (Go): upgrade to 2.2.0 or later

  ```sh
  go get github.com/nats-io/nats-server/v2@v2.2.0
  ```


## Affected products

- github.com/nats-io/jwt (Go) SEMVER:introduced=0,fixed=1.2.3-0.20210314221642-a826c77dc9d2, SEMVER:introduced=0,last_affected=1.2.2
- github.com/nats-io/jwt/v2 (Go) SEMVER:introduced=0,fixed=2.0.1
- github.com/nats-io/nats-server/v2 (Go) SEMVER:introduced=0,fixed=2.2.0

## Identifiers

- CVE-2021-3127
- GHSA-62mh-w5cv-p88c
- GHSA-9r5x-fjv3-q6h4
- GHSA-j756-f273-xhp4
- GO-2022-0386

## Related threats

- [GO-2026-4833 - NATS is vulnerable to MQTT hijacking via Client ID in github.com/nats-io/nats-server](https://junglewise.ai/threats/cve-2026-33215-nats-is-vulnerable-to-mqtt-hijacking-via-client-id)
- [NATS Server: Incomplete Stripping of Nats-Request-Info Header Allows Identity Spoofing](https://junglewise.ai/threats/cve-2026-33223-nats-server-incomplete-stripping-of-nats-request-info-header)
- [GO-2026-4830 - NATS: Leafnode connections allow spoofing of Nats-Request-Info identity headers in github.com/nats-io/nats-server](https://junglewise.ai/threats/cve-2026-33246-nats-leafnode-connections-allow-spoofing-of-nats-request-info)
- [GO-2026-4832 - NATS JetStream has an authorization bypass through its Management API in github.com/nats-io/nats-server](https://junglewise.ai/threats/cve-2026-33222-nats-jetstream-has-an-authorization-bypass-through-its-management)
- [NATS has mTLS verify_and_map authentication bypass via incorrect Subject DN matching](https://junglewise.ai/threats/cve-2026-33248-nats-has-mtls-verify-and-map-authentication-bypass-via-incorrect)