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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-31970 Detail

Description

HTSlib is a library for reading and writing bioinformatics file formats. GZI files are used to index block-compressed GZIP [BGZF] files. In the GZI loading function, `bgzf_index_load_hfile()`, it was possible to trigger an integer overflow, leading to an under- or zero-sized buffer being allocated to store the index. Sixteen zero bytes would then be written to this buffer, and, depending on the result of the overflow the rest of the file may also be loaded into the buffer as well. If the function did attempt to load the data, it would eventually fail due to not reading the expected number of records, and then try to free the overflowed heap buffer. 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. The easiest work-around is to discard any `.gzi` index files from untrusted sources, and use the `bgzip -r` option to recreate them.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
CVSS-B 7.1 HIGH
Vector:  CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
http://www.openwall.com/lists/oss-security/2026/03/18/9 CVE Mailing List  Third Party Advisory 
https://github.com/samtools/htslib/commit/6dd0d7d0e9e7e2e173a28969e624db8bc8bb5828 GitHub, Inc. Patch 
https://github.com/samtools/htslib/security/advisories/GHSA-p345-84hx-fq6q GitHub, Inc. Mitigation  Patch  Vendor Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-122 Heap-based Buffer Overflow GitHub, Inc.  
CWE-131 Incorrect Calculation of Buffer Size GitHub, Inc.  
CWE-190 Integer Overflow or Wraparound GitHub, Inc.  
CWE-787 Out-of-bounds Write GitHub, Inc.  
CWE-1284 Improper Validation of Specified Quantity in Input GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-31970
NVD Published Date:
03/18/2026
NVD Last Modified:
03/19/2026
Source:
GitHub, Inc.