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.
CVE-2026-31973
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 58% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EG Risk
- 38(Track)EG Risk 38/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity75% × 45%Exploitation1% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 1%
- EPSS %ILE
- 43%
- KEV
- Not listed
Published
March 18, 2026
Last Modified
June 17, 2026
Advisory Details (3)
Auto-updated Aug 2, 2026oss-security - CVE-2026-31973: samtools <= 1.23 NULL pointer dereference in cram-size
http://www.openwall.com/lists/oss-security/2026/03/18/12NULL pointer dereference in samtools cram-size · Advisory · samtools/samtools · GitHub
https://github.com/samtools/samtools/security/advisories/GHSA-x86f-q6fj-cm43commit 06fc2a219b3d (samtools/samtools)
Patch available: samtools/samtools 1.24 (contains commit 06fc2a219b3d)
https://github.com/samtools/samtools/commit/06fc2a219b3d7c94d3f412c09f6d1efd51199f2fAffected Packages
(4 across 4 ecosystems)
Debian:11(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| samtools | 1.11-1 ... 1.22.1-1 (19 versions) | — | — |
Debian:12(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| samtools | 1.16.1-1 ... 1.22.1-1 (12 versions) | — | — |
Debian:13(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| samtools | 1.21-1, 1.22.1-1 | — | — |
Debian:14(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| samtools | 1.21-1, 1.22.1-1 | — | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 6× in last 7d / 28× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-09-18 19:28 UTCEPSS rescore
- 2026-09-18 19:27 UTCEPSS rescore
- 2026-09-17 19:30 UTCEPSS rescore
- 2026-09-16 14:08 UTCEPSS rescore
- 2026-09-16 05:15 UTCEPSS rescore
- 2026-09-13 16:47 UTCEPSS rescore
- 2026-09-12 15:01 UTCEPSS rescore
- 2026-09-11 14:52 UTCEPSS rescore
- 2026-09-10 09:34 UTCEPSS rescore
- 2026-09-08 22:00 UTCEPSS rescore
- 2026-09-07 16:01 UTCEPSS rescore
- 2026-09-06 13:47 UTCEPSS rescore
- 2026-09-06 13:47 UTCEPSS rescore
- 2026-09-04 05:06 UTCEPSS rescore
- 2026-09-02 18:08 UTCOSV refresh
- 2026-09-02 14:11 UTCEPSS rescore
- 2026-09-01 13:53 UTCEPSS rescore
- 2026-09-01 04:39 UTCEPSS rescore
- 2026-09-01 04:39 UTCEPSS rescore
- 2026-08-30 19:17 UTCEPSS rescore
- 2026-08-30 01:22 UTCEPSS rescore
- 2026-08-28 21:41 UTCEPSS rescore
- 2026-08-27 14:25 UTCEPSS rescore
- 2026-08-26 14:46 UTCEPSS rescore
- 2026-08-25 13:49 UTCEPSS rescore
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- 2026-08-24 14:17 UTCEPSS rescore
- 2026-08-23 00:19 UTCEPSS rescore
- 2026-08-21 23:49 UTCEPSS rescore
- 2026-08-20 22:55 UTCEPSS rescore
- 2026-08-20 22:55 UTCEPSS rescore
- 2026-08-19 17:03 UTCEPSS rescore
- 2026-08-18 13:48 UTCEPSS rescore
- 2026-08-17 13:47 UTCEPSS rescore
- 2026-08-16 14:56 UTCEPSS rescore
- 2026-08-16 11:14 UTCEG score recompute
- 2026-08-16 02:14 UTCEPSS rescore
- 2026-08-15 01:30 UTCEPSS rescore
- 2026-08-14 07:23 UTCEG score recompute
- 2026-08-13 22:00 UTCEPSS rescore
- 2026-08-12 22:09 UTCEG score recompute
- 2026-08-12 13:50 UTCEPSS rescore
- 2026-08-11 21:30 UTCEG score recompute
- 2026-08-11 04:34 UTCEG score recompute
- 2026-08-11 00:00 UTCEPSS rescore
- 2026-08-09 18:44 UTCEG score recompute
- 2026-08-09 13:46 UTCEPSS rescore
- 2026-08-09 06:57 UTCEG score recompute
- 2026-08-08 16:37 UTCEPSS rescore
- 2026-08-07 17:30 UTCEG score recompute
- 2026-08-06 19:28 UTCEG score recompute
- 2026-08-06 13:46 UTCEPSS rescore
- 2026-08-06 01:37 UTCEG score recompute
- 2026-08-05 19:17 UTCEPSS rescore
- 2026-08-04 15:10 UTCEPSS rescore
- 2026-08-04 10:38 UTCEPSS rescore
- 2026-08-04 00:47 UTCEG score recompute
- 2026-08-03 10:36 UTCEPSS rescore
- 2026-08-02 16:39 UTCEG score recompute
- 2026-08-02 02:27 UTCEPSS rescore
- 2026-08-01 04:16 UTCEPSS rescore
- 2026-07-30 16:28 UTCEPSS rescore
- 2026-07-30 01:30 UTCEPSS rescore
- 2026-07-28 15:36 UTCEPSS rescore
- 2026-07-27 14:41 UTCEG score recompute
- 2026-07-27 14:27 UTCOSV refresh
Frequently asked(5)
What is CVE-2026-31973?
When was CVE-2026-31973 disclosed?
Is CVE-2026-31973 actively exploited?
What is the CVSS score of CVE-2026-31973?
How do I remediate CVE-2026-31973?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-31973
Is Your Infrastructure Affected by CVE-2026-31973?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.