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_LEN` method, the `cram_byte_array_len_decode()` failed to validate that the amount of data being unpacked matched the size of the output buffer where it was to be stored. Depending on the data series being read, this could result either in a heap or a stack overflow with attacker-controlled bytes. 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Htslib | Htslib | < 1.21.1 |
Related Weaknesses (CWE)
References
- https://github.com/samtools/htslib/commit/01cd003b46fa2ebea4d9be5475b11217eb4c11Patch
- https://github.com/samtools/htslib/security/advisories/GHSA-jvx4-4wq7-6fmhPatchVendor Advisory
FAQ
What is CVE-2026-31971?
CVE-2026-31971 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. When...
How severe is CVE-2026-31971?
CVE-2026-31971 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-2026-31971?
Check the references section above for vendor advisories and patch information. Affected products include: Htslib Htslib.