What is the CVSS score of CVE-2020-16904?

CVE-2020-16904 has a CVSS 3.1 base score of 5.3 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N. EPSS exploitation probability: 3.4%.

Which versions of Azure Functions are affected by CVE-2020-16904?

An elevation of privilege vulnerability exists in the way Azure Functions validate access keys. An unauthenticated attacker who successfully exploited this vulnerability could invoke an.. A patch is available.

Is there a patch available for CVE-2020-16904?

Yes, a patch is available for CVE-2020-16904. Update the affected software to the latest version immediately.

Azure Functions CVE-2020-16904

MEDIUM

Incorrect Authorization (CWE-863)

2020-10-16 secure@microsoft.com

Authentication Bypass Microsoft Azure Functions

5.3

CVSS 3.1 · Vendor: microsoft

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Vulnerability Assessment

Weakness	CWE CWE-863 OWASP Top 10:2025 A01:2025 - Broken Access Control ASVS 5.0 V8 - Authorization Authorization logic validation MITRE ATT&CK 1 technique across 1 tactic: Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 5.3 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.
Exploit ScenarioDerived	A remote attacker could bypass authorization checks to access restricted resources by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 3.4% exploitation probability (EPSS)

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AnalysisAI

An elevation of privilege vulnerability exists in the way Azure Functions validate access keys. An unauthenticated attacker who successfully exploited this vulnerability could invoke an. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Incorrect Authorization vulnerability could allow attackers to bypass authorization checks to access restricted resources.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Review and test authorization logic, implement consistent access control checks, use centralized authorization framework.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Incorrect Authorization (CWE-863), which allows attackers to bypass authorization checks to access restricted resources. An elevation of privilege vulnerability exists in the way Azure Functions validate access keys. An unauthenticated attacker who successfully exploited this vulnerability could invoke an HTTP Function without proper authorization. This security update addresses the vulnerability by correctly validating access keys used to access HTTP Functions. Affected products include: Microsoft Azure Functions.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 5.3 MEDIUM

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

Primary rating from Vendor (microsoft) · only source for this CVE.

CVSS VectorVendor: microsoft

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

DescriptionCVE.org

An elevation of privilege vulnerability exists in the way Azure Functions validate access keys. An unauthenticated attacker who successfully exploited this vulnerability could invoke an HTTP Function without proper authorization. This security update addresses the vulnerability by correctly validating access keys used to access HTTP Functions.

Threat Intelligence Overview

EPSS Score

3.4%

Top 13% exploitable

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC No

EPSS 3.4%

Patch available Yes

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.