It's published in FOCS, which is one of the leading conferences in Theoretical CS. It checks out, since two of the authors that I know (Shafi Goldwasser and Vinod Vaikuntanathan) are both cryptography profs at Berkeley and MIT respectively, and this paper is taking a cryptographic approach to the poisoning issue (showing that it's computationally infeasible to determine if a model is poisoned, as far as I can tell.)