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CVE-2026-31972

MEDIUM CVSS 4.0: 6.9 EPSS 0.02%
Updated Mar 19, 2026
Samtools
Parameter Value
CVSS 6.9 (MEDIUM)
Affected Versions before 1.21.1
Fixed In 1.21.1
Type CWE-416 (Use After Free)
Vendor Samtools
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
Low
Partial disruption

CVSS Vector v4.0

Weakness Type (CWE)

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Samtools Samtools
cpe:2.3:a:samtools:samtools:*:*:*:*:*:*:*:*
1.21.1

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