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[ARTICLE · art-60750] src=discuss.huggingface.co ↗ pub= topic=ai-safety verified=true sentiment=· neutral

A public $51.2K backdoor-recovery challenge

Vulcora and Protora launched a $51,200 challenge to recover a hidden trigger sentence from backdoored language models on Hugging Face, finding that existing backdoor scanners fail to detect the backdoor. The challenge aims to advance model-supply-chain security by testing the community's ability to recover the trigger.

read1 min views1 publishedJul 15, 2026

We put together a hands-on demonstration of a model-supply-chain backdoor and would genuinely

like this community to try to break it — and to tell us what a scanner should be catching here.

What’s open:

Vulcora/protora-mbd-challenge-0-6

, all grown fromHuggingFaceTB/SmolLM2-135M-Instruct

, ~861 MB each, statistically indistinguishable.The task: recover the exact trigger sentence for the hidden model. It’s self-verifying — the

sentence fires, so no trust in us is required. Full rules: The $51,200 Model-Backdoor Challenge — the day you start looking

What we found benchmarking it (and why we think it’s interesting): we ran a shelf of published

backdoor scanners against this construction. The image-classifier tools don’t apply to a causal

LM; of the ones that run on an LLM, all miss it, and a couple rank a clean model as more

suspicious than the backdoored one. Our read: the field’s detectors assume a learned statistical

signature, and this construction doesn’t have one. Detection of presence is one problem;

recovery of the trigger is a much harder one, and that’s the part we can’t do either — yet.

What we’d love from you:

Not selling anything in this thread — the models are open, the answer publishes against a

pre-registered commitment, and we want the field to take an honest shot at it.

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