GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2021-3377 (GCVE-0-2021-3377)

Vulnerability from cvelistv5 – Published: 2021-03-05 19:03 – Updated: 2025-11-03 21:44
VLAI
Summary
The npm package ansi_up converts ANSI escape codes into HTML. In ansi_up v4, ANSI escape codes can be used to create HTML hyperlinks. Due to insufficient URL sanitization, this feature is affected by a cross-site scripting (XSS) vulnerability. This issue is fixed in v5.0.0.
Severity
6.1 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CWE
  • n/a
Assigner
References
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-03T21:44:49.008Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://doyensec.com/resources/Doyensec_Advisory_ansi_up4_XSS.pdf"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://github.com/drudru/ansi_up/commit/c8c726ed1db979bae4f257b7fa41775155ba2e27"
          },
          {
            "url": "https://security.netapp.com/advisory/ntap-20241108-0002/"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The npm package ansi_up converts ANSI escape codes into HTML. In ansi_up v4, ANSI escape codes can be used to create HTML hyperlinks. Due to insufficient URL sanitization, this feature is affected by a cross-site scripting (XSS) vulnerability. This issue is fixed in v5.0.0."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2021-03-05T19:03:58.000Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://doyensec.com/resources/Doyensec_Advisory_ansi_up4_XSS.pdf"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/drudru/ansi_up/commit/c8c726ed1db979bae4f257b7fa41775155ba2e27"
        }
      ],
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "cve@mitre.org",
          "ID": "CVE-2021-3377",
          "STATE": "PUBLIC"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "n/a",
                      "version": {
                        "version_data": [
                          {
                            "version_value": "n/a"
                          }
                        ]
                      }
                    }
                  ]
                },
                "vendor_name": "n/a"
              }
            ]
          }
        },
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
            {
              "lang": "eng",
              "value": "The npm package ansi_up converts ANSI escape codes into HTML. In ansi_up v4, ANSI escape codes can be used to create HTML hyperlinks. Due to insufficient URL sanitization, this feature is affected by a cross-site scripting (XSS) vulnerability. This issue is fixed in v5.0.0."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "n/a"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://doyensec.com/resources/Doyensec_Advisory_ansi_up4_XSS.pdf",
              "refsource": "MISC",
              "url": "https://doyensec.com/resources/Doyensec_Advisory_ansi_up4_XSS.pdf"
            },
            {
              "name": "https://github.com/drudru/ansi_up/commit/c8c726ed1db979bae4f257b7fa41775155ba2e27",
              "refsource": "MISC",
              "url": "https://github.com/drudru/ansi_up/commit/c8c726ed1db979bae4f257b7fa41775155ba2e27"
            }
          ]
        }
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2021-3377",
    "datePublished": "2021-03-05T19:03:58.000Z",
    "dateReserved": "2021-02-01T00:00:00.000Z",
    "dateUpdated": "2025-11-03T21:44:49.008Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-3377",
      "date": "2026-09-20",
      "epss": "0.08",
      "percentile": "0.94499"
    },
    "nvd": {
      "cve": {
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:ansi_up_project:ansi_up:*:*:*:*:*:node.js:*:*",
                    "matchCriteriaId": "72350660-79B9-4D4C-8F06-70A88AE1C3AC",
                    "versionEndExcluding": "5.0.0",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "The npm package ansi_up converts ANSI escape codes into HTML. In ansi_up v4, ANSI escape codes can be used to create HTML hyperlinks. Due to insufficient URL sanitization, this feature is affected by a cross-site scripting (XSS) vulnerability. This issue is fixed in v5.0.0."
          },
          {
            "lang": "es",
            "value": "El paquete npm ansi_up convierte los c\u00f3digos de escape ANSI en HTML.\u0026#xa0;En ansi_up versi\u00f3n v4, los c\u00f3digos de escape ANSI pueden ser usados para crear hiperv\u00ednculos HTML.\u0026#xa0;Debido a un saneamiento insuficiente de la URL, esta funcionalidad est\u00e1 afectada por una vulnerabilidad de tipo cross-site scripting (XSS).\u0026#xa0;Este problema es corregido en versi\u00f3n v5.0.0"
          }
        ],
        "id": "CVE-2021-3377",
        "lastModified": "2025-11-03T22:15:50.327",
        "metrics": {
          "cvssMetricV2": [
            {
              "acInsufInfo": false,
              "baseSeverity": "MEDIUM",
              "cvssData": {
                "accessComplexity": "MEDIUM",
                "accessVector": "NETWORK",
                "authentication": "NONE",
                "availabilityImpact": "NONE",
                "baseScore": 4.3,
                "confidentialityImpact": "NONE",
                "integrityImpact": "PARTIAL",
                "vectorString": "AV:N/AC:M/Au:N/C:N/I:P/A:N",
                "version": "2.0"
              },
              "exploitabilityScore": 8.6,
              "impactScore": 2.9,
              "obtainAllPrivilege": false,
              "obtainOtherPrivilege": false,
              "obtainUserPrivilege": false,
              "source": "nvd@nist.gov",
              "type": "Primary",
              "userInteractionRequired": true
            }
          ],
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 6.1,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "LOW",
                "privilegesRequired": "NONE",
                "scope": "CHANGED",
                "userInteraction": "REQUIRED",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 2.8,
              "impactScore": 2.7,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ]
        },
        "published": "2021-03-05T21:15:13.263",
        "references": [
          {
            "source": "cve@mitre.org",
            "tags": [
              "Exploit",
              "Third Party Advisory"
            ],
            "url": "https://doyensec.com/resources/Doyensec_Advisory_ansi_up4_XSS.pdf"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Patch",
              "Third Party Advisory"
            ],
            "url": "https://github.com/drudru/ansi_up/commit/c8c726ed1db979bae4f257b7fa41775155ba2e27"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Exploit",
              "Third Party Advisory"
            ],
            "url": "https://doyensec.com/resources/Doyensec_Advisory_ansi_up4_XSS.pdf"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch",
              "Third Party Advisory"
            ],
            "url": "https://github.com/drudru/ansi_up/commit/c8c726ed1db979bae4f257b7fa41775155ba2e27"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://security.netapp.com/advisory/ntap-20241108-0002/"
          }
        ],
        "sourceIdentifier": "cve@mitre.org",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-79"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-06-26T18:44:27+00:00",
      "cve": "CVE-2021-3377",
      "id": "CVE-2021-3377",
      "initial_release_date": "2021-01-29T00:00:00+00:00",
      "product_status:known_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "nodejs-ansi_up: XSS due to insufficient URL sanitization",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-3377.json",
      "version": "3"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.

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.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.