Accurate estimation of wideband oscillation parameters in power systems can provide essential technical support for oscillation suppression. However, because wideband oscillations share similar frequency ranges with harmonics and interharmonics, extending existing subsynchronous/supersynchronous oscillation estimation to wideband oscillation estimation requires not only overcoming spectrum leakage from the fundamental frequency, but also addressing the coupling and damping characteristics of wideband oscillations. To this end, a window-adjusted interpolated fast Fourier transform (IFFT) and least squares (LS) method are proposed for wideband oscillation estimation. First, the window function is adjusted using a rotation factor, and adjacent spectral-line vector cancellation is applied to obtain interpolated frequency values. Then, based on oscillation characteristics, a peak-extraction function is used to determine the number of components and identify oscillatory components. Finally, LS corrected results are obtained by Taylor series approximation and pseudoinverse matrix solving. Simulation results show that the proposed method can effectively overcome multi-component interference and achieve accurate estimation of random wideband oscillation parameters in the 4 Hz to 2.4 kHz frequency range.