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CVE-2021-46872

Status: ModifiedMedium (6.1)—

An issue was discovered in Nim before 1.6.2. The RST module of the Nim language stdlib, as used in NimForum and other products, permits the javascript: URI scheme and thus can lead to XSS in some applications. (Nim versions 1.6.2 and later are fixed; there may be backports of the fix to some earlier versions. NimForum 2.2.0 is fixed.)

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (2)

Nim-lang — NIMNim-lang — Nimforum

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2021-46872",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2021-46872",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2025-04-07T19:12:45.568123Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 6.1,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 2.7,
        "exploitabilityScore": 2.8
      },
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 6.1,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 2.7,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
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        }
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  ],
  "published": "2023-01-13T06:15:10.940",
  "references": [
    {
      "url": "https://forum.nim-lang.org/t/8852",
      "tags": [
        "Issue Tracking",
        "Vendor Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://github.com/nim-lang/Nim/commit/46275126b89218e64844eee169e8ced05dd0e2d7",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://github.com/nim-lang/Nim/compare/v1.6.0...v1.6.2",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://github.com/nim-lang/Nim/pull/19134",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://github.com/nim-lang/nimforum",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://forum.nim-lang.org/t/8852",
      "tags": [
        "Issue Tracking",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/nim-lang/Nim/commit/46275126b89218e64844eee169e8ced05dd0e2d7",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
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    {
      "url": "https://github.com/nim-lang/Nim/compare/v1.6.0...v1.6.2",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/nim-lang/Nim/pull/19134",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/nim-lang/nimforum",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ]
    },
    {
      "type": "Secondary",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "An issue was discovered in Nim before 1.6.2. The RST module of the Nim language stdlib, as used in NimForum and other products, permits the javascript: URI scheme and thus can lead to XSS in some applications. (Nim versions 1.6.2 and later are fixed; there may be backports of the fix to some earlier versions. NimForum 2.2.0 is fixed.)"
    },
    {
      "lang": "es",
      "value": "Se descubrió un problema en Nim antes de la versión 1.6.2. El módulo RST del lenguaje Nim stdlib, tal como se usa en NimForum y otros productos, permite el esquema javascript: URI y, por lo tanto, puede conducir a XSS en algunas aplicaciones. (Las versiones 1.6.2 y posteriores de Nim están corregidas; puede haber versiones anteriores de la solución para algunas versiones anteriores. NimForum 2.2.0 está corregida)."
    }
  ],
  "lastModified": "2026-06-17T04:15:41.963",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:nim-lang:nim:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "1693ADAF-84A1-4F3D-8C13-C6495A1D91D5",
              "versionEndExcluding": "1.6.2"
            },
            {
              "criteria": "cpe:2.3:a:nim-lang:nimforum:*:*:*:*:*:nim:*:*",
              "vulnerable": true,
              "matchCriteriaId": "FE0421BD-56F6-4822-B2F4-B7B31071BC57",
              "versionEndExcluding": "2.2.0"
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          "operator": "OR"
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  ],
  "sourceIdentifier": "cve@mitre.org"
}