Security Advisory

February 8, 2024 | Posted by Paul

Several security issues affecting Blesta versions 5.0.0 through 5.9.1 have been identified. There is no evidence to suggest that these vulnerabilities are publicly known or being exploited, but you should take action now.

A path traversal vulnerability may lead to account compromise and RCE (Remote Code Execution) through vulnerability chaining. We recommend applying the appropriate patch for your release as soon as possible, or by upgrading to version 5.9.2. Given the compounding nature of these vulnerabilies, we give this an impact rating of Critical.

More information about how we rate vulnerabilities can be found on our Security Advisories page.

Always run /admin/upgrade in your browser after patching or upgrading your installation. Patch releases may only be applied to the minor release to which it belongs, so download the appropriate patch for your minor version. If you are running a version of Blesta between 5.0 and 5.6, upgrade to 5.9.2.


Download 5.9.2 Patch Download 5.9.2 Full



Download 5.8.3 Patch


Download 5.7.2 Patch


To patch your installation, please follow the instructions for Patching an Existing Install from our user manual.


  • If you are running version 5.7.x, apply the 5.7.2 patch above.
  • If you are running version 5.8.x, apply the 5.8.3 patch above.
  • If you are running version 5.9.x, apply the 5.9.2 patch above.
  • If you are running version 5.0.x through 5.6.x, upgrade to 5.9.2 Full.


It is best to upgrade to 5.9.2 or apply the appropriate patch. However, if you are running an affected unsupported version of Blesta (version 5.0 through 5.6), or you need more time to upgrade, you may take the following immediate steps to mitigate.

  • Visit Settings > System > General and note the location of your “Uploads Directory”.
  • Assuming your uploads directory is “/path/to/uploads/” check the directory for your company ID (typically “1”) and see if you have a “themes” directory. If the directory exists, delete the directory. Example locations for this directory are: “/path/to/uploads/1/themes”, “/path/to/uploads/2/themes”, etc. Only users with addon-companies will have any directories other than “1” within the uploads directory. Ensure “themes” is deleted from each.

If your logo dissappears, you may need to visit Settings > Company > Look and Feel > Customize and set your logo using “Set Logo URL”, not “Upload Logo”. NOTE that this may result in the “themes” directory being re-created. If you perform this step, check for and delete the “themes” directory again.

We would also highly recommend ensuring that Two-Factor Authentication is enabled for all Staff accounts. Staff can set up Two-Factor Authentication under “My Info” using a token like Google Authenticator (for iOS/Android).


These issues were reported to us by Emre Hampolat in accordance with our Responsible Disclosure Policy.