CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
Lifecycle Timeline
4Tags
Description
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. For the `VARINT` and `CONST` encodings, incomplete validation of the context in which the encodings were used could result in up to eight bytes being written beyond the end of a heap allocation, or up to eight bytes being written to the location of a one byte variable on the stack, possibly causing the values to adjacent variables to change unexpectedly. Depending on the data stream this could result either in a heap buffer overflow or a stack overflow. If a user opens a file crafted to exploit this issue it could lead to the program crashing, overwriting of data structures on the heap or stack in ways not expected by the program, or changing the control flow of the program. It may be possible to use this to obtain arbitrary code execution. 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 contains a buffer overflow vulnerability in its CRAM format decoder affecting the VARINT and CONST encoding handlers, where incomplete context validation allows writes of up to eight bytes beyond heap allocation boundaries or into stack-allocated single-byte variables. This vulnerability affects HTSlib versions prior to 1.23.1, 1.22.2, and 1.21.1, and impacts any application using the library to process CRAM-formatted bioinformatics data files. …
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Remediation
Within 7 days: Identify all affected systems and apply vendor patches promptly. If patching is delayed, consider network segmentation to limit exposure.
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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-2026-12942