This work shows that the homogeneous black string and black p-branes of Gauss-Bonnet theory in ten dimensions are unstable. The perturbation that we consider is spherically symmetric and it is characterized by a total momentum k along the extended directions. There is a critical wavelength above which the instability is triggered, as it is the case for black strings and black p-branes in General Relativity. The master equation is solved by power series. We observe that the critical wavelength increases with the number of extended directions p, while the maximum exponential growth decreases as p increases.Keywords: Black strings and black p-branes; higher curvature gravity.It's by now well known that black strings and black p-branes in General Relativity (GR) are unstable under long wavelength perturbations travelling along the extended dimensions [1], [2]. For a given mass of the black hole on the brane such behaviour, known as the Gregory-Laflamme (GL) instability, can be avoided if one compactifies the extended directions on a scale smaller than the minimum characteristic wavelength that triggers the instability. This instability have lead to very interesting phenomenology. Concerned by the fact that, due to topological censorship, a naked singularity could be formed if the black string flows to a black hole, Horowitz and Maeda showed that such process could occur only on an infinite affine parameter at the horizon [3]. Non-homogeneous black strings were then constructed perturbatively [4] and numerically [5] in order to obtain stationary configurations that could provide us with a final stage of the instability of black strings. Nevertheless, it was shown that such configurations always have less entropy than the homogeneous black strings for dimensions lower than D = 13, and therefore the unstable black strings could not settle down at the final stage on these configurations [6] (such critical dimension changes for boosted black strings [7]). After a long standing numerical effort [8], [9], the full non-linear evolution of a perturbed unstable black string was achieved in D = 5 [10]. The result show that, as seen by an asymptotic observer, a null naked singularity is indeed formed at a finite time.Before the singularity appears, the black string evolves towards a configuration that can be interpreted as a set of black holes connected by black strings, on a kind of self-similar structure. The naked singularity appears when the transverse radii of such black strings reaches zero. This provides a non-fine tuned counterexample to cosmic censorship in an asymptotically M 4 × S 1 spacetime. A similar phenomenon has been recently reported for the asymptotically flat black ring in D = 5 [11], providing a counterexample of cosmic censorship in an asymptotically M 5 setup.