CVE-2026-116742 (CVSS 4.4)

Description

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.

Is your site exposed to CVE-2026-116742?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

4.4

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L

EPSS — Exploit Prediction

0.0012

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-197 CWE-197

References

Other References

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

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 4.4 (MEDIUM).

How severe is CVE-2026-116742? +

CVE-2026-116742 has a CVSS v3.1 score of 4.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0012, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-116742? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-6039

LibreOffice can import drawings in the DXF format used by CAD software. A heap buffer overflow existed when importing a …

CVE-2026-65610

nnn stores homelen variable as uchar_t, which can only represent values in the range 0-255. An attacker who can influence …

CVE-2026-76151

Out-of-bounds read (buffer over-read) in the HTTP Cache-Control response header parsing in the QtNetwork module in Qt Group Qt 6.0.0 …

CVE-2026-105768

apko allows users to build and publish OCI container images built from apk packages. From version 0.2.0 to before version …

CVE-2026-115889 9.9

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in …

CVE-2026-96113 9.8

Heap-based buffer overflow in DNS Server allows an unauthorized attacker to execute code over a network.

CVE-2026-116742