CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Lifecycle Timeline
4Description
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.
Analysis
HTSlib, a bioinformatics library for reading and writing sequence alignment formats, contains a null pointer dereference vulnerability in its CRAM format decoder affecting versions before 1.23.1, 1.22.2, and 1.21.1. The vulnerability exists in the CONST, XPACK, and XRLE encodings which fail to properly handle CRAM records with omitted sequence or quality data, causing attempts to write to NULL pointers when these records are decoded. …
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Remediation
Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.
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Priority Score
Vendor Status
Debian
| Release | Status | Fixed Version | Urgency |
|---|---|---|---|
| bullseye | vulnerable | 1.11-4 | - |
| bookworm | vulnerable | 1.16+ds-3 | - |
| trixie | vulnerable | 1.21+ds-1 | - |
| forky, sid | vulnerable | 1.22.1+ds2-1 | - |
| (unstable) | fixed | (unfixed) | - |
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External POC / Exploit Code
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EUVD-2026-12932