NULL pointer dereference in Samtools
CVE-2026-31973
SAMtools is a program for reading, manipulating and writing bioinformatics file formats. Starting in version 1.17, in the cram-size command, used to write information about how well CRAM files are compressed, a check to see if the `cram_decode_compression_header()` was missing. If the function returned an error, this could lead to a NULL pointer dereference. 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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (47.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.001
Affected products
- Samtools — versions 1.23, >= 1.22, < 1.22.2, >= 1.17, < 1.21.1
Weakness classification (CWE)
References
- github.com/samtools/samtools/security/advisories/GHSA-x86f-q6fj-cm43 (Vendor Advisory)
- github.com/samtools/samtools/commit/06fc2a219b3d7c94d3f412c09f6d1efd51199f2f (Patch)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-31973?
- CVE-2026-31973 is a high-severity vulnerability in Samtools, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2026-03-18.
- How severe is CVE-2026-31973?
- High severity. CVSS v3 base score is 7.5 out of 10.