CVE-2026-31964: HTSlib CRAM decoder has a NULL Pointer Dereference
HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data using a variety of encodings and compression methods. While most alignment records store DNA sequence and quality values, the format also allows them to omit this data in certain cases to save space. Due to some quirks of the CRAM format, it is necessary to handle these records carefully as they will actually store data that needs to be consumed and then discarded. Unfortunately the CONST, XPACK and XRLE encodings did not properly implement the interface needed to do this. Trying to decode records with omitted sequence or quality data using these encodings would result in an attempt to write to a NULL pointer. Exploiting this bug causes a NULL pointer dereference. Typically this will cause the program to crash. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.
Affected Software
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Frequently Asked Questions
What is the severity of CVE-2026-31964?
CVE-2026-31964 has been classified as a moderate severity vulnerability due to its potential to cause application crashes.
How do I fix CVE-2026-31964?
To fix CVE-2026-31964, update HTSlib to version 1.22.2 or later, or apply the relevant patches.
What types of applications are affected by CVE-2026-31964?
CVE-2026-31964 affects applications that utilize the HTSlib library for processing bioinformatics file formats.
What is the nature of the vulnerability in CVE-2026-31964?
CVE-2026-31964 involves a NULL pointer dereference in the CRAM decoder of HTSlib, leading to potential application failure.
Who is responsible for addressing CVE-2026-31964?
The maintainers of HTSlib are responsible for addressing CVE-2026-31964 by releasing updates and patches.