CVE-2026-107301 (GCVE-0-2026-107301)

Vulnerability from cvelistv5 – Published: 2026-10-08 17:13 – Updated: 2026-10-08 17:13
VLAI
Title
msgpack5: Partial options disable prototype protection
Summary
msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, constructing msgpack5 with an empty or partial options object disables the default protoAction: 'error' protection. A decoded map containing a __proto__ key can then replace the decoded object's prototype, potentially changing inherited properties or downstream behavior, although Object.prototype is not modified globally. This issue is fixed in version 6.1.0.
Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L
CWE
  • CWE-1321 - Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7580 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
mcollina msgpack5 Affected: < 6.1.0
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
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          "versions": [
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        }
      ],
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            "confidentialityImpact": "NONE",
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            "privilegesRequired": "NONE",
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            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L",
            "version": "3.1"
          }
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      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-1321",
              "description": "CWE-1321: Improperly Controlled Modification of Object Prototype Attributes (\u0027Prototype Pollution\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-08T17:13:00.613Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/mcollina/msgpack5/security/advisories/GHSA-8hq7-ggx2-cc6m",
          "tags": [
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          ],
          "url": "https://github.com/mcollina/msgpack5/security/advisories/GHSA-8hq7-ggx2-cc6m"
        },
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          "name": "https://github.com/mcollina/msgpack5/commit/20e82600ac9462e679c8a45e5723315f21e2c774",
          "tags": [
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          "url": "https://github.com/mcollina/msgpack5/commit/20e82600ac9462e679c8a45e5723315f21e2c774"
        },
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          "name": "https://github.com/mcollina/msgpack5/releases/tag/v6.1.0",
          "tags": [
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          "url": "https://github.com/mcollina/msgpack5/releases/tag/v6.1.0"
        }
      ],
      "source": {
        "advisory": "GHSA-8hq7-ggx2-cc6m",
        "discovery": "UNKNOWN"
      },
      "title": "msgpack5: Partial options disable prototype protection"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-107301",
    "datePublished": "2026-10-08T17:13:00.613Z",
    "dateReserved": "2026-10-07T15:53:23.587Z",
    "dateUpdated": "2026-10-08T17:13:00.613Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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                "vendor": "mcollina",
                "versions": [
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          }
        ],
        "id": "CVE-2026-107301",
        "lastModified": "2026-10-08T20:48:36.970",
        "metrics": {
          "cvssMetricV31": [
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              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
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                "baseScore": 6.5,
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                "confidentialityImpact": "NONE",
                "integrityImpact": "HIGH",
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                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L",
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        "references": [
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        "vulnStatus": "Deferred",
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              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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