Bambu Lab Faces Open Source Lawsuit Threat Over Slicer Code

Bambu Lab's Open Source Problem Just Got Official

The Software Freedom Conservancy (SFC) used its FOSSY 2026 stage this week to lay out a detailed case against Bambu Lab. The allegation is simple: Bambu Studio is a modified version of PrusaSlicer, which is licensed under AGPLv3, yet Bambu distributes proprietary networking libraries alongside it without releasing the corresponding source code. For a company that controls an estimated 38 to 48 percent of the $500 to $3,000 desktop printer market, that is not a small oversight.

What the SFC Claims

According to the SFC, Bambu Studio dynamically loads shared library files such as libbambu_networking.so, bambu_networking.dll, and libbambu_networking.dylib. These libraries handle communication with Bambu Lab's cloud servers, and Bambu distributes them only as compiled binaries. Under AGPLv3, any code linked to or communicating intimately with an AGPLv3-covered work must also be released under the same license.

Bambu has publicly acknowledged for years that Bambu Studio is based on PrusaSlicer, which itself grew out of Alessandro Ranellucci's Slic3r project. The SFC says that acknowledgment makes the licensing obligation hard to ignore. The complaint also extends to Bambu printer firmware: the SFC says the company is violating GPLv2 by failing to provide source code for a Buildroot-based Linux firmware used in some models.

The DMCA Takedown That Escalated Things

The issue moved beyond a quiet compliance dispute after Bambu sent a DMCA takedown notice to Polish developer Pawel Jarczak. Jarczak had reverse-engineered the networking protocol and published an OrcaSlicer fork that let users bypass Bambu Studio entirely while still talking to Bambu printers. GitHub honored the takedown, and the SFC now argues that move itself violates AGPLv3's clause against imposing further restrictions.

The SFC has since launched a project called baltobu to reverse-engineer the proprietary libraries, maintain a working OrcaSlicer fork for Bambu printers, and keep a fork of Bambu Studio itself. The goal is to give users a working alternative before any court case reaches a conclusion.

Fundraising Meets Litigation

The SFC's fundraiser for the effort exceeded its $250,000 goal, driven by small donations from makers and open-source advocates. That money is now funding a full-time litigation attorney. Possible legal paths include contract-law claims, direct copyright lawsuits, and even trade-agreement intellectual property clauses, with the SFC citing its previous Vizio case as a model.

Why It Matters to Buyers

Most X2D or P2S owners do not think about software licenses when they unbox a printer. But the dispute touches a practical concern: control. If Bambu Studio's cloud-facing components are proprietary and Bambu can restrict third-party slicers, then users are locked into a single vendor's software stack. The SFC's complaint frames this as a right to repair issue as much as a licensing one.

What Bambu Has Said

Bambu has previously argued that the networking library is protected by anti-circumvention rules and that its terms of service override the open-source license. The SFC calls that reasoning specious and points to the AGPLv3 text, which was specifically written to prevent the network interaction workaround Bambu is accused of using.

What Happens Next

No lawsuit has been filed yet, but the SFC is treating this as an active enforcement matter. The baltobu project is already mirroring code and recruiting volunteers, and the SFC has pledged to monitor Bambu for further copyleft violations. For Bambu Lab, the issue is no longer a Reddit thread or a GitHub argument. It is a funded legal campaign backed by one of the most established open-source enforcement organizations in the United States.