We present the first analysis of an XMM-Newton observation of the nearby molecular cloud MBM 12. We find that in the direction of MBM 12 the total O VII (0.57 keV) triplet emission is 1.8 0.5-0.6 photons cm-2 s-1 sr-1 (or line units, LU) while for the O VIII (0.65 keV) line emission we find a 3? upper limit of <1 LU. We use a heliospheric model to calculate the O VII and O VIII emission generated by Solar Wind Charge-eXchange (SWCX) which we compare to the XMM-Newton observations. This comparison provides new constraints on the relative heliospheric and Local Bubble contributions to the local diffuse X-ray background. The heliospheric SWCX model predicts 0.82 LU for O VII, which accounts for ~46% ± 15% of the observed value, and 0.33 LU for the O VIII line emission consistent with the XMM-Newton observed value. We discuss our results in combination with previous observations of MBM 12 with Chandra and Suzaku.