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.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 5
- StatusPublished → DeferredNVD modified 2026-10-27 16:04
- StatusReceived → PublishedNVD modified 2026-10-27 14:16
- StatusPublished → ReceivedNVD modified 2026-10-27 15:16
- StatusReceived → PublishedNVD modified 2026-10-26 21:52
- First seenCVSS 4.8NVD modified 2026-10-26 22:16
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 7
- https://github.com/samtools/htslib
- https://github.com/samtools/htslib/blob/1.24/bgzf.c#L2504
- https://github.com/samtools/htslib/commit/18dddf02bb2c0053b32acec427723555a24b2873
- https://github.com/samtools/htslib/issues/2113
- https://github.com/samtools/htslib/pull/2057
- https://hackmd.io/@haindpwn/htslib-bgzf-gzi-int-truncation-oob
- https://www.vulncheck.com/advisories/htslib-through-1.24-heap-out-of-bounds-write-via-truncated-gzi-index-count