fix out-of-bounds Xsbr write in hf_assembly sinusoid addition - #224
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fabiangreffrath merged 1 commit intoJun 24, 2026
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hf_assembly guards the top-band sinusoid leak with
if (m + sbr->kx < 64)but writes Xsbr[i + tHFAdj][m + sbr->kx + 1], so when a crafted SBR header makes kx + M reach 64 (the largest value derived_frequency_table allows) the m == M-1 step has m + kx of 63, passes the check, and writes one QMF subband past the 64-wide Xsbr row into the next time slot of the history buffer. The faulty write sits in the SBR_LOW_POWER synthesis path and triggers on a crafted HE-AAC stream whose frequency band layout reaches that boundary. Comparing the index that is actually written keeps the leaked top-band energy from landing out of range.