CVE-2026-31972

6.9 MEDIUM 0.5% exploit odds Fix listed Memory safety

What it is

SAMtools is a program for reading, manipulating and writing bioinformatics file formats. The `mpileup` command outputs DNA sequences that have been aligned against a known reference. On each output line it writes the reference position, optionally the reference DNA base at that position (obtained from a separate file) and all of the DNA bases that aligned to that position. As the output is ordered by position, reference data that is no longer needed is discarded once it has been printed out. Under certain conditions the data could be discarded too early, leading to an attempt to read from a pointer to freed memory. This bug may allow information about program state to be leaked. It may also cause a program crash through an attempt to access invalid memory. This bug is fixed in versions 1.21.1 and 1.22. There is no workaround for this issue.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Exploit odds: 0.5% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-03-18 21:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 10:34 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.5% in the next 30 days (EPSS).
Severity: 6.9 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-03-18 21:16 UTC
Last modified: 2026-06-17 10:34 UTC
Exploit probability: 0.5% · EPSS, next 30 days
Weakness: CWE-416 · Use after free
Record status: Analyzed

Affected

Samtools < 1.21.1

Attack profile CVSS 4.0 · 6.9

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: None
User interaction: None
Confidentiality: Low
Integrity: None
Availability: Low

Raw vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-31972.md and follow it. Check whether this project is affected by CVE-2026-31972. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record