samtools Htslib up to 1.24 bgzf.c bgzf_index_load_hfile out-of-bounds write

Summaryinfo

A vulnerability classified as problematic has been found in samtools Htslib up to 1.24. This affects the function bgzf_index_load_hfile of the file bgzf.c. The manipulation leads to out-of-bounds write. This vulnerability is traded as CVE-2026-116742. An attack has to be approached locally. There is no exploit available.

Detailsinfo

A vulnerability was found in samtools Htslib up to 1.24 and classified as problematic. This issue affects the function bgzf_index_load_hfile of the file bgzf.c. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-116742 since 10/26/2026. The exploitation is known to be easy. An attack has to be approached locally. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• samtools

Name

• Htslib

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24

Website

• Product: https://github.com/samtools/htslib/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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