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Vulnerabilities

Vulnerability · CVE-2026-31962

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-2026-31962. EPSS is 0.61%. 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
High8.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.61%
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. While most alignment records store DNA sequence and quality values, the format also allows them to omit this data in certain cases to save space. Due to some quirks of the CRAM format, it is necessary to handle these records carefully as they will actually store data that needs to be consumed and then discarded. Unfortunately the did not handle this correctly in some cases. Where this happened it could result in reading a single byte from beyond the end of a heap allocation, followed by writing a single attacker-controlled byte to the same location. Exploiting this bug causes a heap buffer overflow. If a user opens a file crafted to exploit this issue, it could lead to the program crashing, or overwriting of data and heap structures in ways not expected by 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-2026-31962

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-2026-31962. EPSS is 0.61%. 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-122: Heap-based Buffer Overflow; CWE-125: Out-of-bounds Read; CWE-129: Improper Validation of Array Index. EPSS 0.61%. 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. While most alignment records store DNA sequence and quality values, the format also allows them to omit this data in certain cases to save space. Due to some quirks of the CRAM format, it is necessary to handle these records carefully as they will actually

  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. While most alignment records store DNA sequence and quality values, the format also allows them to omit this data in certain cases to save space. Due to some quirks of the CRAM format, it is necessary to handle these records carefully as they will actually

Sources

  • CVE.orgVulnerability recordCVE-2026-31962

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-31962

    30-day exploitation probability 0.6%

    first.org
  • NIST NVDVulnerability recordCVE-2026-31962

    HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. While most alignment records store DNA sequence and quality values, the format also allows them to omit this data in certain cases to sav

    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.