CVE-2026-124959

Full vulnerability record from the local CVENow database.

Description

The loadIndex function in nmslib hnswlib and Spotify Voyager does not verify that the element count in a serialized HNSW index is within the stored capacity used to allocate the heap buffer. An attacker can supply a crafted index file with an element count greater than the stored capacity, causing the loader to write beyond the allocated buffer and potentially crash the application when it loads the file.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

[email protected]

Published

2026-11-09 15:17:19.357000

Last modified

2026-11-09 15:17:19.357000

View original CVE JSON

{
  "id": "CVE-2026-124959",
  "sourceIdentifier": "[email protected]",
  "published": "2026-11-09T15:17:19.357",
  "lastModified": "2026-11-09T15:17:19.357",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The loadIndex function in nmslib hnswlib and Spotify Voyager does not verify that the element count in a serialized HNSW index is within the stored capacity used to allocate the heap buffer. An attacker can supply a crafted index file with an element count greater than the stored capacity, causing the loader to write beyond the allocated buffer and potentially crash the application when it loads the file."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Spotify",
          "product": "Voyager",
          "versions": [
            {
              "version": "2.0.7",
              "lessThanOrEqual": "2.1.1",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "hnswlib",
          "product": "hnswlib",
          "versions": [
            {
              "version": "0.5.0",
              "lessThanOrEqual": "0.9.0",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://github.com/nmslib/hnswlib",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/spotify/voyager",
      "source": "[email protected]"
    },
    {
      "url": "https://m00dy.sh/notes/when-an-hnsw-index-lies-about-its-capacity",
      "source": "[email protected]"
    }
  ]
}