What is the CVSS score of CVE-2016-20021?

CVE-2016-20021 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of Jwt Attack are affected by CVE-2016-20021?

Organizations using Gentoo Portage face critical risk from CVE-2016-20021, a signature bypass vulnerability rated CVSS 9.8.. A patch is available.

How to fix or mitigate CVE-2016-20021?

Within 7 days: Identify all affected systems running Gentoo Portage and apply vendor patches promptly. Vendor patch is available.

Jwt Attack CVE-2016-20021

CRITICAL

Improper Verification of Cryptographic Signature (CWE-347)

2024-01-12 cve@mitre.org

Jwt Attack Information Disclosure Portage

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

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

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:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:34 vuln.today

Patch released

Mar 28, 2026 - 19:34 nvd

Patch available

CVE Published

Jan 12, 2024 - 03:15 nvd

CRITICAL 9.8

DescriptionCVE.org

In Gentoo Portage before 3.0.47, there is missing PGP validation of executed code: the standalone emerge-webrsync downloads a .gpgsig file but does not perform signature verification. Unless emerge-webrsync is used, Portage is not vulnerable.

AnalysisAI

In Gentoo Portage before 3.0.47, there is missing PGP validation of executed code: the standalone emerge-webrsync downloads a .gpgsig file but does not perform signature verification. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

Technical ContextAI

This vulnerability is classified under CWE-347. In Gentoo Portage before 3.0.47, there is missing PGP validation of executed code: the standalone emerge-webrsync downloads a .gpgsig file but does not perform signature verification. Unless emerge-webrsync is used, Portage is not vulnerable. Affected products include: Gentoo Portage. Version information: before 3.0.47.

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.