Vulnerability 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. 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Htslib | Htslib | < 1.21.1 |
Related Weaknesses (CWE)
References
- https://github.com/samtools/htslib/commit/88cdf69e4b83bb550ab4f6f7134892c2ad1978Patch
- https://github.com/samtools/htslib/security/advisories/GHSA-q4cj-f4h5-fqgcPatchVendor Advisory
FAQ
What is CVE-2026-31969?
CVE-2026-31969 is a vulnerability with a CVSS score of 8.1 (HIGH). 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. Whe...
How severe is CVE-2026-31969?
CVE-2026-31969 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-31969?
Check the references section above for vendor advisories and patch information. Affected products include: Htslib Htslib.