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Vulnerability record · CVE-2020-36403 · published 1 July 2021

CVE-2020-36403: Htslib out-of-bounds write vulnerability

HHtslib · Htslib

HTSlib through 1.10.2 allows out-of-bounds write access in vcf_parse_format (called from vcf_parse and vcf_read).

8.8 CVSS 3.1 High EPSS 1.6% · top 25.3% CWE-787 · Out-of-bounds write
8.8CVSS 3.1 base score, v2 6.8
1.6%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References, 4 tagged exploit
17 Jun 2026Last modified by NVD

Description

HTSlib through 1.10.2 allows out-of-bounds write access in vcf_parse_format (called from vcf_parse and vcf_read).

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=24097 ExploitIssue TrackingPatchThird Party Advisory
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/htslib/OSV-2020-955.yaml Third Party Advisory
https://github.com/samtools/htslib/commit/dcd4b7304941a8832fba2d0fc4c1e716e7a4e72c PatchThird Party Advisory
https://github.com/samtools/htslib/pull/1447 ExploitThird Party Advisory
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=24097 ExploitIssue TrackingPatchThird Party Advisory
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/htslib/OSV-2020-955.yaml Third Party Advisory
https://github.com/samtools/htslib/commit/dcd4b7304941a8832fba2d0fc4c1e716e7a4e72c PatchThird Party Advisory
https://github.com/samtools/htslib/pull/1447 ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2018-13845Htslib out-of-bounds read vulnerabilityAn issue has been found in HTSlib 1.8. It is a buffer over-read in sam_parse1 in sam.c.EPSS 1.6%9.8CVE-2017-1000206Htslib memory buffer overflow vulnerabilitysamtools htslib library version 1.4.0 and earlier is vulnerable to buffer overflow in the CRAM rANS codec resulting in potential arbitrary code execu…EPSS 2.0%8.8CVE-2026-31968Htslib stack-based buffer overflow vulnerabilityHTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data using a…EPSS 0.52%8.8CVE-2026-31963Htslib heap-based buffer overflow vulnerabilityHTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. As one…EPSS 0.52%8.8CVE-2026-31962Htslib heap-based buffer overflow vulnerabilityHTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. While …EPSS 0.59%7.5CVE-2018-13843Htslib vulnerabilityAn issue has been found in HTSlib 1.8. It is a memory leak in bgzf_getline in bgzf.c. NOTE: the software maintainer's position is that the "failure t…EPSS 1.5%7.5CVE-2018-13844Htslib memory leak vulnerabilityAn issue has been found in HTSlib 1.8. It is a memory leak in fai_read in faidx.c. NOTE: This has been disputed with the assertion that this vulnerab…EPSS 1.4%7.1CVE-2026-31971Htslib stack-based buffer overflow vulnerabilityHTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data using a…EPSS 0.52%

Source: NIST National Vulnerability Database (record CVE-2020-36403), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.