  The circumgalactic medium (CGM) around galaxies is believed to record various
forms of galaxy feedback and contain a significant portion of the "missing
baryons" of individual dark matter halos. However, clear observational evidence
for the existence of the hot CGM is still absent. We use intervening galaxies
along 12 background AGNs as tracers to search for X-ray absorption lines
produced in the corresponding CGM. Stacking Chandra grating observations with
respect to galaxy groups and different luminosities of these intervening
galaxies, we obtain spectra with signal-to-noise ratios of 46-72 per 20-mA
spectral bin at the expected OVII Kalpha line. We find no detectable absorption
lines of CVI, NVII, OVII, OVIII, or NeIX. The high spectral quality allows us
to tightly constrain upper limits to the corresponding ionic column densities
(in particular log[N(OVII)(cm^{-2})]<=14.2--14.8). These nondetections are
inconsistent with the Local Group hypothesis of the X-ray absorption lines at
z~0 commonly observed in the spectra of AGNs. These results indicate that the
putative CGM in the temperature range of 10^{5.5}-10^{6.3} K may not be able to
account for the missing baryons unless the metallicity is less than 10% solar.
