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CVE-2026-31972

Samtools use-after-free

9.8 CRITICALEPSS 0.66%
  1. Published18 Mar 2026

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Samtools< 1.21.1

Frequently asked

Is CVE-2026-31972 being actively exploited?

CVE-2026-31972 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.66%.

How severe is CVE-2026-31972?

CVE-2026-31972 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.66% probability of exploitation.

Which products are affected by CVE-2026-31972?

Affected products include Samtools.

How do I fix CVE-2026-31972?

Upgrade affected software to a fixed version, for example Samtools 1.21.1 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-31972 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.