Vulnerability-Lookup

GHSA-R296-8JJG-794R

Vulnerability from github – Published: 2026-10-27 00:32 – Updated: 2026-10-27 00:32

Details

HTSlib through 1.24 contains a heap out-of-bounds write and read vulnerability in bgzf_index_load_hfile() in bgzf.c that allows attackers to corrupt heap memory by supplying a crafted .gzi index entry count. A count of 0xFFFFFFFF truncates noffs to zero, causing writes past a malloc(0) buffer and an offs[-1] read in bgzf_useek(), resulting in heap corruption or crashes in tools like samtools and bcftools.

Severity

4.4 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L

4.8 (Medium)


                  
                    CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-116742"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-197"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-26T22:16:58Z",
    "severity": "MODERATE"
  },
  "details": "HTSlib through 1.24 contains a heap out-of-bounds write and read vulnerability in bgzf_index_load_hfile() in bgzf.c that allows attackers to corrupt heap memory by supplying a crafted .gzi index entry count. A count of 0xFFFFFFFF truncates noffs to zero, causing writes past a malloc(0) buffer and an offs[-1] read in bgzf_useek(), resulting in heap corruption or crashes in tools like samtools and bcftools.",
  "id": "GHSA-r296-8jjg-794r",
  "modified": "2026-10-27T00:32:48Z",
  "published": "2026-10-27T00:32:48Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-116742"
    },
    {
      "type": "WEB",
      "url": "https://github.com/samtools/htslib/issues/2113"
    },
    {
      "type": "WEB",
      "url": "https://github.com/samtools/htslib/pull/2057"
    },
    {
      "type": "WEB",
      "url": "https://github.com/samtools/htslib/commit/18dddf02bb2c0053b32acec427723555a24b2873"
    },
    {
      "type": "WEB",
      "url": "https://github.com/samtools/htslib"
    },
    {
      "type": "WEB",
      "url": "https://github.com/samtools/htslib/blob/1.24/bgzf.c#L2504"
    },
    {
      "type": "WEB",
      "url": "https://hackmd.io/@haindpwn/htslib-bgzf-gzi-int-truncation-oob"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/htslib-through-1.24-heap-out-of-bounds-write-via-truncated-gzi-index-count"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-116742 (GCVE-0-2026-116742)

Vulnerability from cvelistv5 – Published: 2026-10-26 21:52 – Updated: 2026-10-27 14:16

Title

HTSlib through 1.24 Heap Out-of-Bounds Write via Truncated .gzi Index Count

Summary

Severity

4.8 (Medium)


                        
                          CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

4.4 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-27 13:42 UTC

CWE

CWE-197 - Numeric Truncation Error

Assigner

VulnCheck CNA under the mitre root

CNA scorecard B 84/100 over 7434 records in the last 180 days details

References

7 references

URL	Tags
https://github.com/samtools/htslib/pull/2057	issue-trackingpatch
https://github.com/samtools/htslib/commit/18dddf0…	patch
https://github.com/samtools/htslib	product
https://github.com/samtools/htslib/blob/1.24/bgzf…	technical-description
https://hackmd.io/@haindpwn/htslib-bgzf-gzi-int-t…	third-party-advisory
https://github.com/samtools/htslib/issues/2113	issue-tracking
https://www.vulncheck.com/advisories/htslib-throu…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
samtools	htslib	Affected: 0 , ≤ 1.24 (custom) cpe:2.3:a:htslib:htslib::::::::

Date Public

2026-07-31 00:00

Credits

HaiND from the Post and Telecommunication Institute of Technology daviesrob

Show details on NVD website

JSON

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                "id": "CVE-2026-116742",
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                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-27T13:42:04.833817Z",
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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