What is the CVSS score of CVE-2021-3127?

CVE-2021-3127 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.3%.

Is there a public PoC exploit available for CVE-2021-3127?

Yes, a public proof-of-concept exploit is available for CVE-2021-3127. Prioritise patching immediately. EPSS: 0.3%.

Is there a patch available for CVE-2021-3127?

Yes, a patch is available for CVE-2021-3127. Update the affected software to the latest version immediately.

Nats Server CVE-2021-3127

HIGH

Improper Handling of Exceptional Conditions (CWE-755)

2021-03-16 cve@mitre.org

Information Disclosure Nats Server Jwt Library

7.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.5 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Lifecycle Timeline

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

PoC Detected

Mar 30, 2026 - 14:30 vuln.today

Public exploit code

CVE Published

Mar 16, 2021 - 20:15 nvd

HIGH 7.5

DescriptionCVE.org

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.

AnalysisAI

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. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

Technical ContextAI

This vulnerability is classified under CWE-755. 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. Affected products include: Linuxfoundation Nats-Server, Nats Jwt Library. Version information: before 2.2.0.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.