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Josef Prusa says Bambu Lab allegedly violates AGPL license with an un-auditable network 'black box' — warns Chinese 3D printing software poses massive security risks

2026-05-17 | original

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Why This Matters

Josef Prusa highlights significant security and licensing concerns with Bambu Lab's alleged violation of the AGPL license through its closed-source networking 'black box' in Bambu Studio. This issue underscores the importance of open-source compliance and transparency in the 3D printing industry, which impacts both security and community trust. As Chinese manufacturers expand their market share, maintaining open-source integrity becomes crucial for innovation and security in the industry.

Key Takeaways

Bambu Lab allegedly violates AGPL license with closed-source networking component.
Open-source licenses like AGPL require derivative works to remain open, ensuring transparency.
Security risks arise from un-auditable 'black box' software in 3D printing tools.

While the internet is up in arms over Bambu Lab threatening legal action against an indy OrcaSlicer developer, Josef Prusa once again warns of sheep in wolves' clothing. Prusa, the founder and CEO of Prusa Research and proponent of open source, has often noted that his company is the last Western manufacturer of desktop 3D printers still standing after China began subsidizing manufacturers within its borders.

Prusa recently took to X to explain how the competition has been violating his company’s slicer AGPL-3.0 license since day one, and how that violation is not just an open source issue, but a security issue. While many 3D printing enthusiasts are printing flexi dragons and shelf brackets rather than top secret files, the problem still exists.

First the Open Source Problem in 3D Printing Slicer Software

Prusa Research clearly states in Prusa Slicer’s start-up screen that it is based on Slic3r by Alessandro Ranellucci, despite years of improvement that have, like the Ship of Theseus, slowly replaced the code with improvements.

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Anycubic, Bambu Lab, Creality, Elegoo, Flashforge, Snapmaker, and Sovol all have slicers resting on a foundation laid down by PrusaSlicer. The family tree is quite messy, with some slicers being more directly related to open-source OrcaSlicer, which is a fork of Bambu Studio, which is based on PrusaSlicer.

“BambuStudio has been violating the PrusaSlicer AGPL license since their fork, with the same networking binary black box in question today. Why are they willing to burn the goodwill over it?” Prusa said on X.

PrusaSlicer is licensed under AGPL-3.0 , a strong “copyleft” license that allows users to use, copy, and expand on the original software. The only catch is that you must keep your new derivative open-source as well.

“You take from the community, you give back to the community. That's the social contract,” Prusa said. He said that Bambu’s fork of PrusaSlicer is fine, but the networking plugin is closed-source, which is in violation of AGPL-3.0.

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