How severe is CVE-2026-31973?

CVE-2026-31973 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-31973 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-31973?

CVE-2026-31973 primarily affects Samtools. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-31973?

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

Does CVE-2026-31973 have an EU (EUVD) identifier?

Yes. CVE-2026-31973 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12958.

When was CVE-2026-31973 published?

CVE-2026-31973 was published on 2026-03-18 and last updated on 2026-06-17.

CVE-2026-31973

CVE-2026-31973 is a high-severity vulnerability in Samtools with a CVSS 3.x base score of 7.5. 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-476.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 6.9
EPSS exploit prediction: 1% (41st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-12958
Weakness: CWE-476
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. 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.

Frequently asked questions

What is 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.
How severe is CVE-2026-31973?: CVE-2026-31973 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-31973 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-31973?: CVE-2026-31973 primarily affects Samtools. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-31973?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-31973 have an EU (EUVD) identifier?: Yes. CVE-2026-31973 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12958.
When was CVE-2026-31973 published?: CVE-2026-31973 was published on 2026-03-18 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:samtools:samtools:*:*:*:*:*:*:*:*
cpe:2.3:a:samtools:samtools:1.23:*:*:*:*:*:*:*

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