What is the CVSS score of CVE-2023-5539?

CVE-2023-5539 has a CVSS 3.1 base score of 8.8 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 1.9%.

Is there a patch available for CVE-2023-5539?

Yes, a patch is available for CVE-2023-5539. Update the affected software to the latest version immediately.

Moodle CVE-2023-5539

HIGH

Code Injection (CWE-94)

2023-11-09 patrick@puiterwijk.org

RCE Code Injection Moodle Fedora Extra Packages For Enterprise Linux Fedoraproject

8.8

CVSS 3.1 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-94 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Code injection prevention, sandbox exec MITRE ATT&CK 2 techniques across 2 tactics: Execution, Initial Access 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 8.8 (HIGH). Attack characteristics: network attack vector, low complexity, low privileges required, no user interaction not required.
Exploit ScenarioDerived	A remote attacker could inject and execute arbitrary code within the application by sending crafted requests to the affected application.

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

Patch available 1.9% exploitation probability (EPSS)

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AnalysisAI

A remote code execution risk was identified in the Lesson activity. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. This Code Injection vulnerability could allow attackers to inject and execute arbitrary code within the application.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Never evaluate user-controlled input as code. Use sandboxing, disable dangerous functions, apply strict input validation.

Affected Packages

composer moodle/moodle fix: 4.3.0-rc2

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in composer

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 Code Injection (CWE-94), which allows attackers to inject and execute arbitrary code within the application. A remote code execution risk was identified in the Lesson activity. By default this was only available to teachers and managers. Affected products include: Moodle, Fedoraproject Extra Packages For Enterprise Linux, Fedoraproject Fedora.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 8.8 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionNVD

A remote code execution risk was identified in the Lesson activity. By default this was only available to teachers and managers.

Threat Intelligence Overview

EPSS Score

1.9%

Top 23% 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 HIGH

CISA KEV No

Public POC No

EPSS 1.9%

Patch available Yes

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

None

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +2

CVSS: +44

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.