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Vulnerabilities

Vulnerability · CVE-2026-31971

HTSlib is a library for reading and writing bioinformatics file formats.

Published Mar 18, 2026 · catalog updated Jun 17, 2026 · HTSlib is a library

Check if you run it

No confirmed exploitation is on record for CVE-2026-31971. EPSS is 0.54%. Act only if a listed version of HTSlib is a library is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (HTSlib is a library).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.54%
Remediation
Advisory link
Affected products
cpe htslib/htslib

HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data using a variety of encodings and compression methods. When reading data encoded using the method, the failed to validate that the amount of data being unpacked matched the size of the output buffer where it was to be stored. Depending on the data series being read, this could result either in a heap or a stack overflow with attacker-controlled bytes. Depending on the data stream this could result either in a heap buffer overflow or a stack overflow. If a user opens a file crafted to exploit this issue it could lead to the program crashing, overwriting of data structures on the heap or stack in ways not expected by the program, or changing the control flow of the program. It may be possible to use this to obtain arbitrary code execution. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe htslib/htslib1.23

How to fix CVE-2026-31971

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-31971. EPSS is 0.54%. Act only if a listed version of HTSlib is a library is installed.

Which versions are affected?

Compare what you have installed with 1.23. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-121: Stack-based Buffer Overflow; CWE-122: Heap-based Buffer Overflow; CWE-1284. EPSS 0.54%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 18, 2026 · NIST NVD

    Detected

    HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data using a variety of encodings and compression methods. When reading data encoded using the method, the failed to validate that the amount of data being unpacked matched the size of the output buffer where it was to be stored. Depending on the data series bein

  2. Jun 17, 2026 · NIST NVD

    Updated

    HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data using a variety of encodings and compression methods. When reading data encoded using the method, the failed to validate that the amount of data being unpacked matched the size of the output buffer where it was to be stored. Depending on the data series bein

Sources

  • CVE.orgVulnerability recordCVE-2026-31971

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-31971

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-31971

    HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data using a variety of encodings and compression methods. When reading data encoded using the method, the `cram_byte_array_le

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.