CVE-2026-116742

HTSlib through 1.24 contains a heap out-of-bounds write and read vulnerability in bgzf index load hfile() in bgzf.c that allows attackers to corrupt heap memory by supplying a crafted .gzi index entry count. A count of 0xFFFFFFFF truncates noffs to zero, causing writes past a malloc(0) buffer and an offs[-1] read in bgzf useek(), resulting in heap corruption or crashes in tools like samtools and bcftools.