How severe is CVE-2026-31972?

CVE-2026-31972 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-31972 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-31972?

CVE-2026-31972 affects Samtools. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-31972?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-31972 have an EU (EUVD) identifier?

Yes. CVE-2026-31972 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12956.

When was CVE-2026-31972 published?

CVE-2026-31972 was published on 2026-03-18 and last updated on 2026-06-17.

CVE-2026-31972

CVE-2026-31972 is a critical-severity vulnerability in Samtools with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 6.9
EPSS exploit prediction: 1% (40th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-12956
Weakness: CWE-416
Affected product: Samtools
Published: 2026-03-18
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-31972?: 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.
How severe is CVE-2026-31972?: CVE-2026-31972 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-31972 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-31972?: CVE-2026-31972 affects Samtools. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-31972?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-31972 have an EU (EUVD) identifier?: Yes. CVE-2026-31972 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12956.
When was CVE-2026-31972 published?: CVE-2026-31972 was published on 2026-03-18 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:samtools:samtools:*:*:*:*:*:*:*:*

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