Heap Buffer Overflow Vulnerability in HTSlib Library by Samtools
CVE-2026-31969

7.1HIGH

Key Information:

Vendor

Samtools

Status
Htslib
Vendor
CVE Published:
18 March 2026

What is CVE-2026-31969?

The HTSlib library, utilized for bioinformatics file formats, faces a severe security flaw due to an out-of-bounds write when processing data encoded with the BYTE_ARRAY_STOP method. This vulnerability allows an attacker to manipulate the output buffer, leading to potential program crashes and unpredictable alterations to data and heap structures. If exploited, it could enable arbitrary code execution by opening specially crafted files. The issue has been addressed in HTSlib versions 1.23.1, 1.22.2, and 1.21.1, with no workaround available.

Affected Version(s)

htslib < 1.21.1 < 1.21.1

htslib >= 1.22, < 1.22.2 < 1.22, 1.22.2

htslib = 1.23 = 1.23

References

https://github.com/samtools/htslib/security/advisories/GH...
x_refsource_CONFIRM
https://github.com/samtools/htslib/commit/88cdf69e4b83bb5...
x_refsource_MISC

CVSS V4

Score:
7.1
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.