Prusa accuses Bambu Lab of AGPL violation warns Chinese 3D risks

Josef Prusa, founder of Prusa Research, has accused Bambu Lab of violating the AGPL-3.0 license through an un-auditable network “black box” in its 3D printer software. The claim centers on a cloud plugin that users rely on for convenience, which Prusa argues cannot be independently verified. This, he says, creates a potential security risk tied to China’s regulatory framework.

Prusa Slicer, the open-source software Prusa Research developed, introduced opt-in telemetry in 2021. That same year, Prusa’s team noticed unexpected data entries labeled “BambuSlicer” in their database. Internal builds from Bambu Lab had accidentally sent telemetry to Prusa’s servers instead of their own, revealing a fork of the software before Bambu Lab’s public launch. Prusa Research chose not to pursue legal action at the time, citing the difficulty of enforcing software licenses without physical products.

Today, the dispute resurfaces as Bambu Lab faces legal threats over its Bambu Studio software. Prusa argues the cloud plugin and Bambu Studio are functionally one product, split into two files to avoid licensing issues. Users who rely on the cloud for printing—often new users unfamiliar with manual file transfers—depend on the plugin, which is downloaded from a CDN and can be remotely updated. Prusa says this makes auditing impossible, raising concerns about hidden capabilities.

China’s regulatory environment adds another layer to the controversy. Prusa points to a five-law framework enacted between 2017 and 2023, requiring citizens to assist in intelligence gathering and hand over encryption keys to the government. He warns that even well-intentioned individuals in China may be legally bound to comply with state demands. This, he says, could allow foreign companies operating in China to be complicit in surveillance or data extraction efforts.

Prusa highlights the strategic importance of 3D printing to China’s innovation ecosystem. 3D printers are commonly used in R&D labs, university workshops, and defense industries—places where new ideas are born. If a slicer software like Bambu Studio has access to the same data as users, it could theoretically expose sensitive information. Prusa extends this concern beyond 3D printing, suggesting similar risks exist in industries like AI, automotive, and photography.

The case of Naomi Wu, a Chinese tech reviewer who disappeared from public view in 2023 after warning about spyware in a keyboard app, is cited as an example of the risks faced by individuals who challenge state interests. Prusa’s tweet linking to the five-law framework underscores his belief that China’s legal system leaves little room for neutrality in tech operations.

It has not responded to the allegations, while Prusa Research continues to emphasize the need for transparency in software development practices.

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