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Vulnerability record · CVE-2026-34161 · published 14 April 2026

CVE-2026-34161: Chamilo lms cross-site scripting vulnerability

Chamilo · Chamilo Lms

Chamilo LMS is an open-source learning management system. In versions prior to 2.0.0-RC.3, a Stored Cross-Site Scripting (XSS) vulnerability exists in the social post attachment upload functionality, where an authenticated user can upload a malicious HTML file containing JavaScript via the /api/social_post_attachments endpoint. The uploaded file is served back from the application at the generated contentUrl without sanitization, content type restrictions, or a Content-Disposition: attachment header, causing the JavaScript to execute in the browser within the application's origin. Because the payload is stored server-side and runs in the trusted origin, an attacker can perform session hijacking, account takeover, privilege escalation (if an admin views the link), and arbitrary actions on behalf of the victim. This issue has been fixed in version 2.0.0-RC.3.

5.1 CVSS 4.0 Medium EPSS 0.31% · top 79.0% CWE-79 · Cross-site scripting
5.1CVSS 4.0 base score
0.31%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
24 Jul 2026Last modified by NVD

Description

Chamilo LMS is an open-source learning management system. In versions prior to 2.0.0-RC.3, a Stored Cross-Site Scripting (XSS) vulnerability exists in the social post attachment upload functionality, where an authenticated user can upload a malicious HTML file containing JavaScript via the /api/social_post_attachments endpoint. The uploaded file is served back from the application at the generated contentUrl without sanitization, content type restrictions, or a Content-Disposition: attachment header, causing the JavaScript to execute in the browser within the application's origin. Because the payload is stored server-side and runs in the trusted origin, an attacker can perform session hijacking, account takeover, privilege escalation (if an admin views the link), and arbitrary actions on behalf of the victim. This issue has been fixed in version 2.0.0-RC.3.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/chamilo/chamilo-lms/commit/7c4965e48769d1d06413836429e386816a465c7f Patch
https://github.com/chamilo/chamilo-lms/commit/da671d66a146887be3a16eabc5dcf0a92c55f7da Patch
https://github.com/chamilo/chamilo-lms/releases/tag/v2.0.0-RC.3 ProductRelease Notes
https://github.com/chamilo/chamilo-lms/security/advisories/GHSA-273p-jw9w-3g22 Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2026-33707Chamilo lms weak password recovery vulnerabilityChamilo LMS is a learning management system. Prior to 1.11.38 and 2.0.0-RC.3, the default password reset mechanism generates tokens using sha1($email…EPSS 0.75%9.8CVE-2025-50187Chamilo lms vulnerabilityChamilo is a learning management system. Prior to version 1.11.28, parameter from SOAP request is evaluated without filtering which leads to Remote C…EPSS 0.90%9.8CVE-2023-34944Chamilo lms unrestricted file upload vulnerabilityAn arbitrary file upload vulnerability in the /fileUpload.lib.php component of Chamilo 1.11.* up to v1.11.18 allows attackers to execute arbitrary co…EPSS 1.1%9.8CVE-2022-27423Chamilo lms sql injection vulnerabilityChamilo LMS v1.11.13 was discovered to contain a SQL injection vulnerability via the blog_id parameter at /blog/blog.php.EPSS 0.99%9.8CVE-2021-35414Chamilo lms sql injection vulnerabilityChamilo LMS v1.11.x was discovered to contain a SQL injection via the doc parameter in main/plagiarism/compilatio/upload.php.EPSS 1.9%9.8CVE-2019-13082Chamilo lms unrestricted file upload vulnerabilityChamilo LMS 1.11.8 and 2.x allows remote code execution through an lp_upload.php unauthenticated file upload feature. It extracts a ZIP archive befor…EPSS 4.0%9.8CVE-2018-1999019Chamilo lms code injection vulnerabilityChamilo LMS version 11.x contains an Unserialization vulnerability in the "hash" GET parameter for the api endpoint located at /webservices/api/v2.ph…EPSS 3.2%9.3CVE-2026-33698Chamilo lms vulnerabilityChamilo LMS is a learning management system. Prior to 1.11.38, a chained attack can enable otherwise-blocked PHP code from the main/install/ director…EPSS 0.58%

Source: NIST National Vulnerability Database (record CVE-2026-34161), CISA KEV, FIRST EPSS (scores of 2026-10-01). This page is refreshed as NVD updates the record.