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.
CVE-2026-31972
“—” beside the score: it is equal to NVD's CVSS score.
This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.5% (46th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Also known asEUVD-2026-12956 (ENISA EUVD)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 9.8
- EG Score
- 9.8CRITICALmedium confidence
- EG Risk
- 59EG Risk 59/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity98% × 45%Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.5% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.5%
- EPSS %ILE
- 46th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
March 18, 2026
Last Modified
June 17, 2026
Advisory Details (3)
Auto-updated Oct 31, 2026oss-security - CVE-2026-31972: samtools <= 1.21 Use-after-free in mpileup leading to an invalid read
http://www.openwall.com/lists/oss-security/2026/03/18/11Use-after-free in samtools mpileup leading to an invalid read · Advisory · samtools/samtools · GitHub
Affected: versions 1.21.1 and 1.22
https://github.com/samtools/samtools/security/advisories/GHSA-72c8-4jf3-f27pcommit 3036eb9af945 (samtools/samtools)
Patch available: samtools/samtools 1.23 (contains commit 3036eb9af945)
https://github.com/samtools/samtools/commit/3036eb9af945fcef359427a2d359855553da4adfAffected Packages
(4 across 4 ecosystems)
Debian:11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| samtools | 1.11-1 ... 1.22.1-1 (19 versions) |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| samtools | 1.16.1-1 ... 1.24-2 (14 versions) |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| samtools | 1.21-1, 1.22.1-1, 1.24-1, 1.24-2 |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| samtools | 1.21-1 |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 7× in last 7d / 31× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.
Showing the most recent 100 of 152 rows on record for this CVE, as 98 entries (2 repeats merged).
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 2 repeat rows among the latest 100 are merged into the row they repeat. The 52 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-13 05:48 UTCEchelonGraph re-scored
- 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.5% · 46th percentile
- 2026-11-12 07:49 UTCEchelonGraph re-scored
- 2026-11-11 16:39 UTCEPSS rescoreEPSS 0.5% · 46th percentile
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- 2026-11-10 16:43 UTCEPSS rescoreEPSS 0.5% · 46th percentile
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- 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.5% · 46th percentile
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- 2026-11-08 16:39 UTCEPSS rescoreEPSS 0.5% · 46th percentile
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- 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.5% · 46th percentile
- 2026-11-06 19:47 UTCEchelonGraph re-scored
- 2026-11-06 16:37 UTCEPSS rescoreEPSS 0.5% · 46th percentile
- 2026-11-06 05:55 UTCOSV refresh
- 2026-11-05 21:48 UTCEchelonGraph re-scored
- 2026-11-05 16:37 UTCEPSS rescoreEPSS 0.5% · 46th percentile
- 2026-11-04 23:49 UTCEchelonGraph re-scored
- 2026-11-04 16:35 UTCEPSS rescoreEPSS 0.5% · 46th percentile
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- 2026-11-03 16:47 UTCEPSS rescoreEPSS 0.5% · 45th percentile
- 2026-11-03 03:50 UTCEchelonGraph re-scored
- 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.5% · 45th percentile
- 2026-11-02 05:50 UTCEchelonGraph re-scored
- 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.5% · 45th percentile
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- 2026-11-01 07:51 UTCEchelonGraph re-scored
- 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
- 2026-10-31 09:50 UTCEchelonGraph re-scored
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.5% · 45th percentile
- 2026-10-30 11:51 UTCEchelonGraph re-scored
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
- 2026-10-29 13:53 UTCEchelonGraph re-scored
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
- 2026-10-27 17:54 UTCEchelonGraph re-scored
- 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.5% · 45th percentile
- 2026-10-26 19:54 UTCEchelonGraph re-scored
- 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.5% · 44th percentile
- 2026-10-25 19:39 UTCEchelonGraph re-scored
- 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
- 2026-10-25 14:36 UTCEchelonGraph re-scored
- 2026-10-24 21:39 UTCEchelonGraph re-scored
- 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-23 23:40 UTCEchelonGraph re-scored
- 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-23 01:04 UTCEchelonGraph re-scored
- 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-22 02:19 UTCEchelonGraph re-scored
- 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
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- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 51st percentile
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- 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.7% · 51st percentile
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- 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.7% · 51st percentile
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- 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-10-17 06:23 UTCEchelonGraph re-scored
- 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.7% · 51st percentile
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- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
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- 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-10-14 02:24 UTCEchelonGraph re-scored
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-10-12 22:38 UTCEchelonGraph re-scored
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-10-12 16:14 UTCEchelonGraph re-scored
- 2026-10-11 19:57 UTCEchelonGraph re-scored
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- 2026-10-11 14:38 UTCEchelonGraph re-scored
- 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-10-11 08:55 UTCOSV refresh
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.7% · 49th percentile
- 2026-09-21 21:45 UTCOSV refresh
- 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
- 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
Related CVEs(same product + same CWE)
Frequently asked(5)
What is CVE-2026-31972?
When was the CVE record for CVE-2026-31972 published?
Is CVE-2026-31972 actively exploited?
What is the CVSS score of CVE-2026-31972?
How do I remediate CVE-2026-31972?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-31972
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