HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. In the `cram_decode_slice()` function called while reading CRAM records, validation of the reference id field occurred too late, allowing two out of bounds reads to occur before the invalid data was detected. The bug does allow two values to be leaked to the caller, however as the function reports an error it may be difficult to exploit them. It is also possible that the program will crash due to trying to access invalid memory. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.

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History

Thu, 19 Mar 2026 09:45:00 +0000

Type Values Removed Values Added
First Time appeared Samtools
Samtools htslib
Vendors & Products Samtools
Samtools htslib

Thu, 19 Mar 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.6, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:H'}

threat_severity

Moderate


Wed, 18 Mar 2026 19:00:00 +0000

Type Values Removed Values Added
Description HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. In the `cram_decode_slice()` function called while reading CRAM records, validation of the reference id field occurred too late, allowing two out of bounds reads to occur before the invalid data was detected. The bug does allow two values to be leaked to the caller, however as the function reports an error it may be difficult to exploit them. It is also possible that the program will crash due to trying to access invalid memory. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.
Title HTSlib CRAM reader has out-of-bounds reads due to improper validation of input
Weaknesses CWE-125
CWE-129
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-18T18:50:37.333Z

Reserved: 2026-03-10T15:40:10.484Z

Link: CVE-2026-31965

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-03-18T19:16:04.823

Modified: 2026-03-18T19:16:04.823

Link: CVE-2026-31965

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-03-18T18:50:37Z

Links: CVE-2026-31965 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-03-19T08:55:42Z

Weaknesses