CVE-2026-116742medium4.8
HTSlib through 1.24 Heap Out-of-Bounds Write via Truncated .gzi Index Count
The advisory, in context
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.
Affected packages
This source has no supported package-version data for matching. You can read the advisory here, but this record alone cannot power a dependency check.
Start with the recorded fix for your release branch. Check your installed version and test compatibility before upgrading. Fixing this advisory does not rule out other vulnerabilities in the release.
References
- https://github.com/samtools/htslib/pull/2057
- https://github.com/samtools/htslib/commit/18dddf02bb2c0053b32acec427723555a24b2873
- https://github.com/samtools/htslib
- https://github.com/samtools/htslib/blob/1.24/bgzf.c#L2504
- https://hackmd.io/@haindpwn/htslib-bgzf-gzi-int-truncation-oob
- https://github.com/samtools/htslib/issues/2113
- https://www.vulncheck.com/advisories/htslib-through-1.24-heap-out-of-bounds-write-via-truncated-gzi-index-count