HTSlib is a library for reading and writing bioinformatics file formats. CRAM is a compressed format which stores DNA sequence alignment data. In the cram_decode_slice() function called while reading CRAM records, the value of the mate reference id field was not validated. Later use of this value, for example when converting the data to SAM format, could result in the out of bounds array reads when looking up the corresponding reference name. If the array value obtained also happened to be a valid pointer, it would be interpreted as a string and an attempt would be made to write the data as part of the SAM record. 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. Versions 1.23.1, 1.22.2 and 1.21.1 include fixes for this issue. There is no workaround for this issue.
CVE-2026-31967
This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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
- 9.1
- EG Score
- 9.1(low)
- EG Risk
- 45(Track)EG Risk 45/100SSVC: 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 computedSeverity91% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
Published
March 18, 2026
Last Modified
June 17, 2026
Advisory Details (2)
Auto-updated Jul 27, 2026Out-of-bounds read in HTSlib CRAM reader due to improper validation of input · Advisory · samtools/htslib · GitHub
https://github.com/samtools/htslib/security/advisories/GHSA-33x5-c6vj-8f2wcommit 9cefb46453ad (samtools/htslib)
Patch available: samtools/htslib 1.23.1 (contains commit 9cefb46453ad)
https://github.com/samtools/htslib/commit/9cefb46453ad471e933b8212d4f45920524d3357Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 2× in last 7d / 2× 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.
- 2026-07-27 14:41 UTCEG score recompute
- 2026-07-27 14:27 UTCOSV refresh
Related CVEs(same CWE)
Same CWE
10 shownCWE-125 · CWE-129
Frequently asked(4)
What is CVE-2026-31967?
When was CVE-2026-31967 disclosed?
What is the CVSS score of CVE-2026-31967?
How do I remediate CVE-2026-31967?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-31967
Is Your Infrastructure Affected by CVE-2026-31967?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.