CVE-2026-31973

NULL pointer dereference in samtools cram-size

CVSS 6.9 MEDIUMEPSS 0.5%CWE-476

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 6.9EPSS 0.5%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

18 Mar 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Affected products

samtools · samtools

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References

https://github.com/samtools/samtools/commit/06fc2a219b3d7c94d3f412c09f6d1efd51199f2f https://github.com/samtools/samtools/security/advisories/GHSA-x86f-q6fj-cm43 http://www.openwall.com/lists/oss-security/2026/03/18/12