  Stable non-supersymmetric Anti-de Sitter (AdS) vacua of string theory are
widely believed not to exist. In this letter, we analytically compute the full
bosonic Kaluza-Klein spectrum around the ${\rm G_2}$-invariant
non-supersymmetric $\textrm{AdS}_4$ solution of massive IIA supergravity, and
show that it is perturbatively stable. We also provide evidence that six other
non-supersymmetric $\textrm{AdS}_4$ solutions of massive IIA supergravity are
perturbatively stable. Since previous studies have indicated that these AdS
vacua may also be non-perturbatively stable, our findings pose a challenge to
the Swampland Conjecture.
