What is the CVSS score of CVE-2025-53021?

CVE-2025-53021 has a CVSS 3.1 base score of 4.2 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N. EPSS exploitation probability: 0.2%.

How to fix or mitigate CVE-2025-53021?

Within 30 days: Identify affected systems running Moodle 3.x and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.

Moodle CVE-2025-53021

EUVD-2025-19060 MEDIUM

Session Fixation (CWE-384)

2025-06-24 cve@mitre.org

GHSA-cgvv-3455-824j

Information Disclosure Debian Ubuntu Moodle

4.2

CVSS 3.1 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-384 OWASP Top 10:2025 A07:2025 - Authentication Failures ASVS 5.0 V7 - Session Management Session fixation prevention
Impact	CVSS score of 4.2 (MEDIUM).

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

Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 15, 2026

A session fixation vulnerability in Moodle 3.x through 3.11.18 allows unauthenticated attackers to hijack user sessions via the sesskey parameter. The sesskey can be obtained without authentication and reused within the OAuth2 login flow, resulting in the victim's session being linked to the attacker's. Successful exploitation results in full account takeover. According to the Moodle Releases page, "Bug fixes for security issues in 3.11.x ended 11 December 2023." NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

Earlier versions of this analysis (1)

v1 Mar 15, 2026 - 22:36 CVSS 4.2

RemediationAI

Monitor vendor advisories for patches. Apply mitigations such as network segmentation, access restrictions, and monitoring.

Affected VersionsENISA

Moodle 3 ≤3.11.18

Affected Packages

composer moodle/moodle fix: 4.0.0

euvd moodle no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in composer, euvd

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 Session Fixation (CWE-384).

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 4.2 MEDIUM

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

Ubuntu MEDIUM

Primary rating from NVD.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

CVE Published

Jun 24, 2025 - 20:15 nvd

MEDIUM 4.2

Executive ViewAI

Why It Matters

Organizations using Moodle 3.x should be aware of moderate risk from CVE-2025-53021 rated CVSS 4.2. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Low

Compensating Controls

Apply vendor patch. If patching is delayed: restrict network access and enable monitoring.

Threat Intelligence Overview

EPSS Score

0.2%

Top 58% exploitable

Data Quality

6 sources

Confidence: High

EUVD

NVD

CVE.org

EPSS Vendor

GitHub

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 0.2%

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.

SSVC AssessmentENISA

SSVC Decision· derived

Defer

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Human Impact

Low

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +21

PoC: 0

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.