EUVD-2026-12944
CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/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. When reading data encoded using the `BYTE_ARRAY_STOP` method, an out-by-one error in the `cram_byte_array_stop_decode_char()` function check for a full output buffer could result in a single attacker-controlled byte being written beyond the end of a heap allocation. Exploiting this bug causes a heap buffer overflow. If a user opens a file crafted to exploit this issue, it could lead to the program crashing, or overwriting of data and heap structures in ways not expected by 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 versions prior to 1.21.1, 1.22.2, and 1.23.1 contain an out-by-one error in the CRAM decoder's `cram_byte_array_stop_decode_char()` function that allows a single attacker-controlled byte to be written beyond the end of a heap allocation. This heap buffer overflow (CWE-122) affects bioinformatics applications using HTSlib to process CRAM-formatted DNA sequence alignment files, and could enable arbitrary code execution if exploited. …
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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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