The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using $^{3}\mathrm{He}$ as a buffer gas. At $T=1.8\text{ }\text{ }\mathrm{K}$ this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with $^{4}\mathrm{He}$. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range $0.39\text{ }\text{ }\mathrm{eV}\ensuremath{\lesssim}{m}_{a}\ensuremath{\lesssim}0.64\text{ }\text{ }\mathrm{eV}$. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of ${g}_{a\ensuremath{\gamma}}\ensuremath{\lesssim}2.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$ at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to ${m}_{a}\ensuremath{\lesssim}1.15\text{ }\text{ }\mathrm{eV}$, comfortably overlapping with cosmological hot dark matter bounds.