OctoPrint provides a web interface for controlling consumer 3D printers. Prior to 1.11.8 and 2.0.0rc3, Suppressed Command notification popups use PNotify rendering for printer-controlled payload.command and payload.message values in src/octoprint/static/js/app/viewmodels/terminal.js without HTML escaping. An attacker who convinces a victim to print a crafted file can inject HTML and JavaScript into the notification, disrupt prints, read information available to the victim including sensitive settings when permitted, or perform actions in the victim's OctoPrint session. This issue is fixed in versions 1.11.8 and 2.0.0rc3.

Affected: PyPI: OctoPrint

### Impact

OctoPrint versions up to and including 1.11.7 as well as 2.0.0rc1 and 2.0.0rc2 are affected by a vulnerability that allows injection of arbitrary HTML and JavaScript into Suppressed Command notifications popups generated by the printer.

An attacker who successfully convinces a victim to print a specially crafted file could exploit this issue to disrupt ongoing prints, extract information (including sensitive configuration settings, if the targeted user has the necessary permissions for that), or perform other actions on behalf of the targeted user within the OctoPrint instance.

### Patches

The vulnerability has been patched in version 1.11.8 and 2.0.0rc3.

### Workaround

OctoPrint administrators can mitigate the risk by disabling popups: - for Action Command notifications, set _OctoPrint Settings -> Serial Connection -> Behaviour -> Sanity Checking -> Display notifications for suppressed commands_ to _Never show notifications_

It is also strongly recommended to ensure that files being printed originate from trusted sources, and, whenever possible, are sliced with an application's own slicer.

### Credits

This vulnerability was discovered and responsibly disclosed to OctoPrint by [Jacopo Tediosi](https://github.com/jacopotediosi).

### Timeline

2026-03-18: Report received 2026-04-01: Report verified 2026-04-01: Fix ready for 2.0.0 2026-06-22: Fix backported to 1.11.x 2026-06-23: Fix released with 1.11.8 and 2.0.0rc3

Affected: PyPI: octoprint

### Impact

OctoPrint versions up to and including 1.11.7 as well as 2.0.0rc1 and 2.0.0rc2 are affected by a vulnerability that allows injection of arbitrary HTML and JavaScript into Suppressed Command notifications popups generated by the printer.

An attacker who successfully convinces a victim to print a specially crafted file could exploit this issue to disrupt ongoing prints, extract information (including sensitive configuration settings, if the targeted user has the necessary permissions for that), or perform other actions on behalf of the targeted user within the OctoPrint instance.

### Patches

The vulnerability has been patched in version 1.11.8 and 2.0.0rc3.

### Workaround

OctoPrint administrators can mitigate the risk by disabling popups: - for Action Command notifications, set _OctoPrint Settings -> Serial Connection -> Behaviour -> Sanity Checking -> Display notifications for suppressed commands_ to _Never show notifications_

It is also strongly recommended to ensure that files being printed originate from trusted sources, and, whenever possible, are sliced with an application's own slicer.

### Credits

This vulnerability was discovered and responsibly disclosed to OctoPrint by [Jacopo Tediosi](https://github.com/jacopotediosi).

### Timeline

2026-03-18: Report received 2026-04-01: Report verified 2026-04-01: Fix ready for 2.0.0 2026-06-22: Fix backported to 1.11.x 2026-06-23: Fix released with 1.11.8 and 2.0.0rc3