Using the REX-ISOLDE facility at CERN the Coulomb excitation cross sections for the 0+gs→2+1 transition in the β-unstable isotopes Cd100,102,104 have been measured for the first time. Two different targets were used, which allows for the first extraction of the static electric quadrupole moments Q(2+1) in Cd102,104. In addition to the B(E2) values in Cd102,104, a first experimental limit for the B(E2) value in Cd100 is presented. The data was analyzed using the maximum likelihood method. The provided probability distributions impose a test for theoretical predictions of the static and dynamic moments. The data are interpreted within the shell-model using realistic matrix elements obtained from a G-matrix renormalized CD-Bonn interaction. In view of recent results for the light Sn isotopes the data are discussed in the context of a renormalization of the neutron effective charge. This study is the first to use the reorientation effect for post-accelerated short-lived radioactive isotopes to simultaneously determine the B(E2) and the Q(2+1) values.