What is the CVSS score of CVE-2021-31540?

CVE-2021-31540 has a CVSS 3.1 base score of 7.1 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. EPSS exploitation probability: 0.4%.

Is there a public PoC exploit available for CVE-2021-31540?

Yes, a public proof-of-concept exploit is available for CVE-2021-31540. Prioritise patching immediately. EPSS: 0.4%.

Streaming Engine CVE-2021-31540

HIGH

Incorrect Permission Assignment for Critical Resource (CWE-732)

2021-04-23 cve@mitre.org

Information Disclosure Streaming Engine Wowza

7.1

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-732 OWASP Top 10:2025 A01:2025 - Broken Access Control ASVS 5.0 V13 - Configuration Permission assignment review
Impact	CVSS score of 7.1 (HIGH). Attack characteristics: local attack vector, low complexity, low privileges required, no user interaction not required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	A local attacker with access to the system could access resources due to misconfigured permissions.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAI

Wowza Streaming Engine through 4.8.5 (in a default installation) has incorrect file permissions of configuration files in the conf/ directory. Rated high severity (CVSS 7.1), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Review and restrict file/resource permissions, apply principle of least privilege.

Affects your stack

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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 Permission Assignment (CWE-732), which allows attackers to access resources due to misconfigured permissions. Wowza Streaming Engine through 4.8.5 (in a default installation) has incorrect file permissions of configuration files in the conf/ directory. A regular local user is able to read and write to all the configuration files, e.g., modify the application server configuration. Affected products include: Wowza Streaming Engine. Version information: through 4.8.5.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.1 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

DescriptionNVD

Wowza Streaming Engine through 4.8.5 (in a default installation) has incorrect file permissions of configuration files in the conf/ directory. A regular local user is able to read and write to all the configuration files, e.g., modify the application server configuration.

Threat Intelligence Overview

EPSS Score

0.4%

Top 69% exploitable

Exploit

POC

Public exploit code exists

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 HIGH

CISA KEV No

Public POC Yes

EPSS 0.4%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

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.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

Poc

System Exposure· derived

Small

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +36

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.