CVE-2021-48012 (GCVE-0-2021-48012)

Vulnerability from cvelistv5 – Published: 2026-10-12 20:55 – Updated: 2026-10-12 20:55
VLAI
Title
fast-toml through 0.5.4 Prototype Pollution via __proto__ Keys in Parsed TOML
Summary
fast-toml through 0.5.4 contains a prototype pollution vulnerability that allows attackers to modify Object.prototype by supplying TOML containing __proto__, constructor or prototype key segments. Attackers can pass [__proto__] or [constructor.prototype] table headers or __proto__.x dotted keys to parse() to pollute all objects, causing denial of service or authorization bypass.
Severity
8.8 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
8.2 (High)
CVSS:3.1/AV:N/AC:L/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
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 6031 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Gin-Quin fast-toml Affected: 0 , ≤ 0.5.4 (semver)
guessed Create a notification for this product.
Date Public
2021-01-14 00:00
Credits
Abdulloh Nuriddinov Asjidkalam gnsehfvlr
Show details on NVD website
To clipboard 

{
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          "product": "fast-toml",
          "repo": "https://github.com/Gin-Quin/fast-toml",
          "vendor": "Gin-Quin",
          "versions": [
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              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
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          "type": "finder",
          "value": "Abdulloh Nuriddinov"
        },
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        }
      ],
      "metrics": [
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            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
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            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
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          },
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      "problemTypes": [
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          "descriptions": [
            {
              "cweId": "CWE-1321",
              "description": "Improperly Controlled Modification of Object Prototype Attributes (\u0027Prototype Pollution\u0027)",
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              "type": "CWE"
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          ]
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      "providerMetadata": {
        "dateUpdated": "2026-10-12T20:55:05.966Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
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      "references": [
        {
          "name": "GitHub Issue #8",
          "tags": [
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          ],
          "url": "https://github.com/Gin-Quin/fast-toml/issues/8"
        },
        {
          "name": "GitHub Pull Request #3",
          "tags": [
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          "url": "https://github.com/Gin-Quin/fast-toml/pull/3"
        },
        {
          "tags": [
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          "url": "https://github.com/Gin-Quin/fast-toml"
        },
        {
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          "tags": [
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          ],
          "url": "https://www.vulncheck.com/advisories/fast-toml-through-0.5.4-prototype-pollution-via-proto-keys-in-parsed-toml"
        }
      ],
      "title": "fast-toml through 0.5.4 Prototype Pollution via __proto__ Keys in Parsed TOML",
      "x_generator": {
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    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2021-48012",
    "datePublished": "2026-10-12T20:55:05.966Z",
    "dateReserved": "2026-10-12T19:37:38.614Z",
    "dateUpdated": "2026-10-12T20:55:05.966Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-10-14",
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        "cveTags": [],
        "descriptions": [
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            "value": "fast-toml through 0.5.4 contains a prototype pollution vulnerability that allows attackers to modify Object.prototype by supplying TOML containing __proto__, constructor or prototype key segments. Attackers can pass [__proto__] or [constructor.prototype] table headers or __proto__.x dotted keys to parse() to pollute all objects, causing denial of service or authorization bypass."
          }
        ],
        "id": "CVE-2021-48012",
        "lastModified": "2026-10-12T21:17:06.057",
        "metrics": {
          "cvssMetricV31": [
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                "attackVector": "NETWORK",
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                "baseSeverity": "HIGH",
                "confidentialityImpact": "NONE",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
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                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
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                "exploitMaturity": "NOT_DEFINED",
                "integrityRequirement": "NOT_DEFINED",
                "modifiedAttackComplexity": "NOT_DEFINED",
                "modifiedAttackRequirements": "NOT_DEFINED",
                "modifiedAttackVector": "NOT_DEFINED",
                "modifiedPrivilegesRequired": "NOT_DEFINED",
                "modifiedSubAvailabilityImpact": "NOT_DEFINED",
                "modifiedSubConfidentialityImpact": "NOT_DEFINED",
                "modifiedSubIntegrityImpact": "NOT_DEFINED",
                "modifiedUserInteraction": "NOT_DEFINED",
                "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
                "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
                "modifiedVulnIntegrityImpact": "NOT_DEFINED",
                "privilegesRequired": "NONE",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
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                "userInteraction": "NONE",
                "valueDensity": "NOT_DEFINED",
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            "source": "disclosure@vulncheck.com",
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            "source": "disclosure@vulncheck.com",
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}



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