Bug 2448775 (CVE-2026-31967)

Summary:	CVE-2026-31967 htslib: HTSlib: Information disclosure and Denial of Service via unvalidated CRAM mate reference ID
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	Keywords:	Security
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in HTSlib, a library used for bioinformatics file formats. When processing CRAM (Compressed Reference-oriented Alignment Map) records, the `cram_decode_slice()` function fails to validate the mate reference ID field. This oversight allows an attacker to craft a malicious CRAM file, which can lead to an out-of-bounds read during data conversion to SAM (Sequence Alignment/Map) format. The primary consequence of this vulnerability is the potential disclosure of sensitive program state information, and it may also cause a Denial of Service (DoS) by crashing the program.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2448887, 2448890, 2448891, 2448877, 2448881
Bug Blocks:

Description OSIDB Bzimport 2026-03-18 20:02:12 UTC

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, the value of the mate reference id field was not validated. Later use of this value, for example when converting the data to SAM format, could result in the out of bounds array reads when looking up the corresponding reference name. If the array value obtained also happened to be a valid pointer, it would be interpreted as a string and an attempt would be made to write the data as part of the SAM record. This bug may allow information about program state to be leaked. It may also cause a program crash through an attempt 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.