CVE-2026-31970

8.1 HIGH
Published: March 18, 2026 Modified: March 19, 2026
View on NVD

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.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

Login to generate AI explanation

CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/samtools/htslib/security/advisories/GHSA-p345-84hx-fq6q
Source: security-advisories@github.com
Mitigation Patch Vendor Advisory
http://www.openwall.com/lists/oss-security/2026/03/18/9
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
8.1 / 10.0
EPSS (Exploit Probability)
0.0%
13th percentile
Exploitation Status
Not in CISA KEV

Affected Vendors

htslib