Auth bypass in Chamilo Chamilo-Lms
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.
Vulnerability class: Broken Authentication
EPSS: 0.002 (11.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.
Affected products
- Chamilo Chamilo-lms — versions >= 2.0-RC.2, < 2.0-RC.3
- Chamilo Chamilo_lms — versions 2.0.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-33715?
- CVE-2026-33715 is a high-severity vulnerability in Chamilo Chamilo-Lms, classified under Missing Authentication for Critical Function. CVSS score: 7.2/10. Published 2026-04-14.
- How severe is CVE-2026-33715?
- High severity. CVSS v3 base score is 7.2 out of 10.
- Is CVE-2026-33715 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.