Information disclosure and crash via premature reference eviction
Published Mar 18, 2026 · Updated Mar 18, 2026
Use-after-free in Samtools mpileup 1.21 and earlier allows context-dependent attackers to disclose process memory or crash the command. The mplp_get_ref cache retains only two references, although mpileup -a can require three in-flight references, so it discards data that output generation still reads. Triggering requires the -a option and alignments for one reference that all start at the same position; effects are bounded to memory disclosure or process termination.
Summary
What happened
Use-after-free in Samtools mpileup 1.21 and earlier allows context-dependent attackers to disclose process memory or crash the command. The mplp_get_ref cache retains only two references, although mpileup -a can require three in-flight references, so it discards data that output generation still reads. Triggering requires the -a option and alignments for one reference that all start at the same position; effects are bounded to memory disclosure or process termination.
The record
- CVE
- CVE-2026-31972
- Published
- Mar 18, 2026
- Updated
- Mar 18, 2026
- Vendor
- Samtools
- Product
- Samtools
- Classifications
- CWE-416, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 18, 2026CVE publishedPublication date reported by the CVE source.
- Mar 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=< 1.21.1
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What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Technologies
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Your stack
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