CVE-2026-33715: Chamilo LMS is an open-source learning management system. In version 2.0-RC.2, the file public/main/inc/ajax/install.ajax.php is accessible without au...

Description

Chamilo LMS is an open-source learning management system. In version 2.0-RC.2, the file public/main/inc/ajax/install.ajax.php is accessible without authentication on fully installed instances because, unlike other AJAX endpoints, it does not include the global.inc.php file that performs authentication and installation-completed checks. Its test_mailer action accepts an arbitrary Symfony Mailer DSN string from POST data and uses it to connect to an attacker-specified SMTP server, enabling Server-Side Request Forgery (SSRF) into internal networks via the SMTP protocol. An unauthenticated attacker can also abuse this to weaponize the Chamilo server as an open email relay for phishing and spam campaigns, with emails appearing to originate from the server's IP address. Additionally, error responses from failed SMTP connections may disclose information about internal network topology and running services. This issue has been fixed in version 2.0.0-RC.3.

Metrics

CVSS 3.1

7.2/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

EPSS Probability

0.21%

10.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Chamilo	Chamilo Lms	2.0.0	Rc2

References

https://github.com/chamilo/chamilo-lms/releases/tag/v2.0.0-RC.3Product, Release Notes
https://github.com/chamilo/chamilo-lms/security/advisories/GHSA-mxc9-9335-45mcVendor Advisory

Timeline

Published: Apr 14, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-33715?

Chamilo LMS is an open-source learning management system. In version 2.0-RC.2, the file public/main/inc/ajax/install.ajax.php is accessible without authentication on fully installed instances because, unlike other AJAX endpoints, it does not include the global.inc.php file that performs authentication and installation-completed checks. Its test_mailer action accepts an arbitrary Symfony Mailer DSN string from POST data and uses it to connect to an attacker-specified SMTP server, enabling Server-Side Request Forgery (SSRF) into internal networks via the SMTP protocol. An unauthenticated attacker can also abuse this to weaponize the Chamilo server as an open email relay for phishing and spam campaigns, with emails appearing to originate from the server's IP address. Additionally, error responses from failed SMTP connections may disclose information about internal network topology and running services. This issue has been fixed in version 2.0.0-RC.3.

How severe is CVE-2026-33715?

CVE-2026-33715 has a CVSS score of 7.2/10 (HIGH severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.

How do I fix CVE-2026-33715?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.