Moodle mybackpack Functionality Server Side Request Forgery Vulnerability [CVE-2019-3809]

CVE Number – CVE-2019-3809

A vulnerability in the mybackpack functionality of Moodle could allow an unauthenticated, remote attacker to conduct a Server Side Request Forgery (SSRF) attack on a targeted system.The vulnerability exists because Moodle incorrectly allows the setting of badge URLs. An attacker could exploit this vulnerability by submitting requests to the affected software. A successful exploit could allow the attacker to conduct an SSRF attack on the targeted system.Moodle has confirmed this vulnerability and released software updates.


  • To exploit this vulnerability, the attacker must send a malicious request to the targeted system, making exploitation more difficult in environments that restrict network access from untrusted sources.


  • Administrators are advised to apply the appropriate updates.    
    Administrators are advised to allow only trusted users to have network access.    
    Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.    
    Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.    
    Administrators can help protect affected systems from external attacks by using a solid firewall strategy.    
    Administrators are advised to monitor affected systems.

Vendor Announcements

  • Moodle has issued a security advisory at the following link: MSA-19-0002

Fixed Software

  • Moodle has released a software update at the following link: 3.6.3+

Duncan Newell

Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.

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