CVE-2021-28957 (GCVE-0-2021-28957)

Vulnerability from cvelistv5 – Published: 2021-03-21 04:39 – Updated: 2025-12-17 21:31
VLAI
Summary
An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
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": "2024-08-03T21:55:12.376Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://bugs.launchpad.net/lxml/+bug/1888153"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
          },
          {
            "name": "[debian-lts-announce] 20210324 [SECURITY] [DLA 2606-1] lxml security update",
            "tags": [
              "mailing-list",
              "x_refsource_MLIST",
              "x_transferred"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
          },
          {
            "name": "DSA-4880",
            "tags": [
              "vendor-advisory",
              "x_refsource_DEBIAN",
              "x_transferred"
            ],
            "url": "https://www.debian.org/security/2021/dsa-4880"
          },
          {
            "name": "FEDORA-2021-28723f9670",
            "tags": [
              "vendor-advisory",
              "x_refsource_FEDORA",
              "x_transferred"
            ],
            "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45/"
          },
          {
            "name": "FEDORA-2021-4cdb0f68c7",
            "tags": [
              "vendor-advisory",
              "x_refsource_FEDORA",
              "x_transferred"
            ],
            "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ/"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
          },
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
          },
          {
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://security.netapp.com/advisory/ntap-20210521-0004/"
          },
          {
            "name": "GLSA-202208-06",
            "tags": [
              "vendor-advisory",
              "x_refsource_GENTOO",
              "x_transferred"
            ],
            "url": "https://security.gentoo.org/glsa/202208-06"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "cvssV3_1": {
              "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"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2021-28957",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-12-17T21:31:40.372887Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-79",
                "description": "CWE-79 Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-12-17T21:31:43.446Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "An XSS vulnerability was discovered in python-lxml\u0027s clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2022-08-10T05:06:44.000Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://bugs.launchpad.net/lxml/+bug/1888153"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
        },
        {
          "name": "[debian-lts-announce] 20210324 [SECURITY] [DLA 2606-1] lxml security update",
          "tags": [
            "mailing-list",
            "x_refsource_MLIST"
          ],
          "url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
        },
        {
          "name": "DSA-4880",
          "tags": [
            "vendor-advisory",
            "x_refsource_DEBIAN"
          ],
          "url": "https://www.debian.org/security/2021/dsa-4880"
        },
        {
          "name": "FEDORA-2021-28723f9670",
          "tags": [
            "vendor-advisory",
            "x_refsource_FEDORA"
          ],
          "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45/"
        },
        {
          "name": "FEDORA-2021-4cdb0f68c7",
          "tags": [
            "vendor-advisory",
            "x_refsource_FEDORA"
          ],
          "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ/"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
        },
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
        },
        {
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://security.netapp.com/advisory/ntap-20210521-0004/"
        },
        {
          "name": "GLSA-202208-06",
          "tags": [
            "vendor-advisory",
            "x_refsource_GENTOO"
          ],
          "url": "https://security.gentoo.org/glsa/202208-06"
        }
      ],
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "cve@mitre.org",
          "ID": "CVE-2021-28957",
          "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": "An XSS vulnerability was discovered in python-lxml\u0027s clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "n/a"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://bugs.launchpad.net/lxml/+bug/1888153",
              "refsource": "MISC",
              "url": "https://bugs.launchpad.net/lxml/+bug/1888153"
            },
            {
              "name": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270",
              "refsource": "MISC",
              "url": "https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270"
            },
            {
              "name": "[debian-lts-announce] 20210324 [SECURITY] [DLA 2606-1] lxml security update",
              "refsource": "MLIST",
              "url": "https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html"
            },
            {
              "name": "DSA-4880",
              "refsource": "DEBIAN",
              "url": "https://www.debian.org/security/2021/dsa-4880"
            },
            {
              "name": "FEDORA-2021-28723f9670",
              "refsource": "FEDORA",
              "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45/"
            },
            {
              "name": "FEDORA-2021-4cdb0f68c7",
              "refsource": "FEDORA",
              "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ/"
            },
            {
              "name": "https://www.oracle.com/security-alerts/cpuoct2021.html",
              "refsource": "MISC",
              "url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
            },
            {
              "name": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999",
              "refsource": "MISC",
              "url": "https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999"
            },
            {
              "name": "https://security.netapp.com/advisory/ntap-20210521-0004/",
              "refsource": "CONFIRM",
              "url": "https://security.netapp.com/advisory/ntap-20210521-0004/"
            },
            {
              "name": "GLSA-202208-06",
              "refsource": "GENTOO",
              "url": "https://security.gentoo.org/glsa/202208-06"
            }
          ]
        }
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2021-28957",
    "datePublished": "2021-03-21T04:39:35.000Z",
    "dateReserved": "2021-03-21T00:00:00.000Z",
    "dateUpdated": "2025-12-17T21:31:43.446Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-28957",
      "date": "2026-05-29",
      "epss": "0.00518",
      "percentile": "0.67031"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-28957\",\"sourceIdentifier\":\"cve@mitre.org\",\"published\":\"2021-03-21T05:15:13.367\",\"lastModified\":\"2025-12-17T22:15:56.740\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"An XSS vulnerability was discovered in python-lxml\u0027s clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.\"},{\"lang\":\"es\",\"value\":\"Se ha descubierto una vulnerabilidad XSS en las versiones del m\u00f3dulo clean de python-lxml anteriores a la versi\u00f3n 4.6.3. Al desactivar los argumentos safe_attrs_only y forms, la clase Cleaner no elimina el atributo formaction, lo que permite que JS eluda el sanitizador. Un atacante remoto podr\u00eda aprovechar este fallo para ejecutar c\u00f3digo JS arbitrario en usuarios que interact\u00faen con HTML incorrectamente saneado. Este problema est\u00e1 parcheado en lxml  versi\u00f3n 4.6.3\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N\",\"baseScore\":6.1,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"REQUIRED\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.8,\"impactScore\":2.7},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N\",\"baseScore\":6.1,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"REQUIRED\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.8,\"impactScore\":2.7}],\"cvssMetricV2\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"2.0\",\"vectorString\":\"AV:N/AC:M/Au:N/C:N/I:P/A:N\",\"baseScore\":4.3,\"accessVector\":\"NETWORK\",\"accessComplexity\":\"MEDIUM\",\"authentication\":\"NONE\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"PARTIAL\",\"availabilityImpact\":\"NONE\"},\"baseSeverity\":\"MEDIUM\",\"exploitabilityScore\":8.6,\"impactScore\":2.9,\"acInsufInfo\":false,\"obtainAllPrivilege\":false,\"obtainUserPrivilege\":false,\"obtainOtherPrivilege\":false,\"userInteractionRequired\":true}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-79\"}]},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-79\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:lxml:lxml:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"4.6.3\",\"matchCriteriaId\":\"2BADE2D9-D321-4DB0-839C-EB11673439DD\"}]}]},{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"DEECE5FC-CACF-4496-A3E7-164736409252\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"07B237A9-69A3-4A9C-9DA0-4E06BD37AE73\"}]}]},{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"E460AA51-FCDA-46B9-AE97-E6676AA5E194\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"A930E247-0B43-43CB-98FF-6CE7B8189835\"}]}]},{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:netapp:snapcenter:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"BDFB1169-41A0-4A86-8E4F-FDA9730B1E94\"}]}]},{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"D3E503FB-6279-4D4A-91D8-E237ECF9D2B0\"}]}]}],\"references\":[{\"url\":\"https://bugs.launchpad.net/lxml/+bug/1888153\",\"source\":\"cve@mitre.org\",\"tags\":[\"Exploit\",\"Issue Tracking\",\"Third Party Advisory\"]},{\"url\":\"https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999\",\"source\":\"cve@mitre.org\",\"tags\":[\"Patch\",\"Third Party Advisory\"]},{\"url\":\"https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270\",\"source\":\"cve@mitre.org\",\"tags\":[\"Patch\",\"Third Party Advisory\"]},{\"url\":\"https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html\",\"source\":\"cve@mitre.org\",\"tags\":[\"Mailing List\",\"Third Party Advisory\"]},{\"url\":\"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45/\",\"source\":\"cve@mitre.org\"},{\"url\":\"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ/\",\"source\":\"cve@mitre.org\"},{\"url\":\"https://security.gentoo.org/glsa/202208-06\",\"source\":\"cve@mitre.org\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"https://security.netapp.com/advisory/ntap-20210521-0004/\",\"source\":\"cve@mitre.org\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"https://www.debian.org/security/2021/dsa-4880\",\"source\":\"cve@mitre.org\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"https://www.oracle.com/security-alerts/cpuoct2021.html\",\"source\":\"cve@mitre.org\",\"tags\":[\"Patch\",\"Third Party Advisory\"]},{\"url\":\"https://bugs.launchpad.net/lxml/+bug/1888153\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Exploit\",\"Issue Tracking\",\"Third Party Advisory\"]},{\"url\":\"https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\",\"Third Party Advisory\"]},{\"url\":\"https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\",\"Third Party Advisory\"]},{\"url\":\"https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Mailing List\",\"Third Party Advisory\"]},{\"url\":\"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45/\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ/\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"https://security.gentoo.org/glsa/202208-06\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"https://security.netapp.com/advisory/ntap-20210521-0004/\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"https://www.debian.org/security/2021/dsa-4880\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"https://www.oracle.com/security-alerts/cpuoct2021.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\",\"Third Party Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://bugs.launchpad.net/lxml/+bug/1888153\", \"tags\": [\"x_refsource_MISC\", \"x_transferred\"]}, {\"url\": \"https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270\", \"tags\": [\"x_refsource_MISC\", \"x_transferred\"]}, {\"url\": \"https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html\", \"name\": \"[debian-lts-announce] 20210324 [SECURITY] [DLA 2606-1] lxml security update\", \"tags\": [\"mailing-list\", \"x_refsource_MLIST\", \"x_transferred\"]}, {\"url\": \"https://www.debian.org/security/2021/dsa-4880\", \"name\": \"DSA-4880\", \"tags\": [\"vendor-advisory\", \"x_refsource_DEBIAN\", \"x_transferred\"]}, {\"url\": \"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45/\", \"name\": \"FEDORA-2021-28723f9670\", \"tags\": [\"vendor-advisory\", \"x_refsource_FEDORA\", \"x_transferred\"]}, {\"url\": \"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ/\", \"name\": \"FEDORA-2021-4cdb0f68c7\", \"tags\": [\"vendor-advisory\", \"x_refsource_FEDORA\", \"x_transferred\"]}, {\"url\": \"https://www.oracle.com/security-alerts/cpuoct2021.html\", \"tags\": [\"x_refsource_MISC\", \"x_transferred\"]}, {\"url\": \"https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999\", \"tags\": [\"x_refsource_MISC\", \"x_transferred\"]}, {\"url\": \"https://security.netapp.com/advisory/ntap-20210521-0004/\", \"tags\": [\"x_refsource_CONFIRM\", \"x_transferred\"]}, {\"url\": \"https://security.gentoo.org/glsa/202208-06\", \"name\": \"GLSA-202208-06\", \"tags\": [\"vendor-advisory\", \"x_refsource_GENTOO\", \"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-03T21:55:12.376Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"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\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2021-28957\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2025-12-17T21:31:40.372887Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-79\", \"description\": \"CWE-79 Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2025-12-17T21:31:20.854Z\"}}], \"cna\": {\"affected\": [{\"vendor\": \"n/a\", \"product\": \"n/a\", \"versions\": [{\"status\": \"affected\", \"version\": \"n/a\"}]}], \"references\": [{\"url\": \"https://bugs.launchpad.net/lxml/+bug/1888153\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html\", \"name\": \"[debian-lts-announce] 20210324 [SECURITY] [DLA 2606-1] lxml security update\", \"tags\": [\"mailing-list\", \"x_refsource_MLIST\"]}, {\"url\": \"https://www.debian.org/security/2021/dsa-4880\", \"name\": \"DSA-4880\", \"tags\": [\"vendor-advisory\", \"x_refsource_DEBIAN\"]}, {\"url\": \"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45/\", \"name\": \"FEDORA-2021-28723f9670\", \"tags\": [\"vendor-advisory\", \"x_refsource_FEDORA\"]}, {\"url\": \"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ/\", \"name\": \"FEDORA-2021-4cdb0f68c7\", \"tags\": [\"vendor-advisory\", \"x_refsource_FEDORA\"]}, {\"url\": \"https://www.oracle.com/security-alerts/cpuoct2021.html\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://security.netapp.com/advisory/ntap-20210521-0004/\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://security.gentoo.org/glsa/202208-06\", \"name\": \"GLSA-202208-06\", \"tags\": [\"vendor-advisory\", \"x_refsource_GENTOO\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"An XSS vulnerability was discovered in python-lxml\u0027s clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"text\", \"description\": \"n/a\"}]}], \"providerMetadata\": {\"orgId\": \"8254265b-2729-46b6-b9e3-3dfca2d5bfca\", \"shortName\": \"mitre\", \"dateUpdated\": \"2022-08-10T05:06:44.000Z\"}, \"x_legacyV4Record\": {\"affects\": {\"vendor\": {\"vendor_data\": [{\"product\": {\"product_data\": [{\"version\": {\"version_data\": [{\"version_value\": \"n/a\"}]}, \"product_name\": \"n/a\"}]}, \"vendor_name\": \"n/a\"}]}}, \"data_type\": \"CVE\", \"references\": {\"reference_data\": [{\"url\": \"https://bugs.launchpad.net/lxml/+bug/1888153\", \"name\": \"https://bugs.launchpad.net/lxml/+bug/1888153\", \"refsource\": \"MISC\"}, {\"url\": \"https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270\", \"name\": \"https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270\", \"refsource\": \"MISC\"}, {\"url\": \"https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html\", \"name\": \"[debian-lts-announce] 20210324 [SECURITY] [DLA 2606-1] lxml security update\", \"refsource\": \"MLIST\"}, {\"url\": \"https://www.debian.org/security/2021/dsa-4880\", \"name\": \"DSA-4880\", \"refsource\": \"DEBIAN\"}, {\"url\": \"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45/\", \"name\": \"FEDORA-2021-28723f9670\", \"refsource\": \"FEDORA\"}, {\"url\": \"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ/\", \"name\": \"FEDORA-2021-4cdb0f68c7\", \"refsource\": \"FEDORA\"}, {\"url\": \"https://www.oracle.com/security-alerts/cpuoct2021.html\", \"name\": \"https://www.oracle.com/security-alerts/cpuoct2021.html\", \"refsource\": \"MISC\"}, {\"url\": \"https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999\", \"name\": \"https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999\", \"refsource\": \"MISC\"}, {\"url\": \"https://security.netapp.com/advisory/ntap-20210521-0004/\", \"name\": \"https://security.netapp.com/advisory/ntap-20210521-0004/\", \"refsource\": \"CONFIRM\"}, {\"url\": \"https://security.gentoo.org/glsa/202208-06\", \"name\": \"GLSA-202208-06\", \"refsource\": \"GENTOO\"}]}, \"data_format\": \"MITRE\", \"description\": {\"description_data\": [{\"lang\": \"eng\", \"value\": \"An XSS vulnerability was discovered in python-lxml\u0027s clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.\"}]}, \"problemtype\": {\"problemtype_data\": [{\"description\": [{\"lang\": \"eng\", \"value\": \"n/a\"}]}]}, \"data_version\": \"4.0\", \"CVE_data_meta\": {\"ID\": \"CVE-2021-28957\", \"STATE\": \"PUBLIC\", \"ASSIGNER\": \"cve@mitre.org\"}}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-28957\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2025-12-17T21:31:43.446Z\", \"dateReserved\": \"2021-03-21T00:00:00.000Z\", \"assignerOrgId\": \"8254265b-2729-46b6-b9e3-3dfca2d5bfca\", \"datePublished\": \"2021-03-21T04:39:35.000Z\", \"assignerShortName\": \"mitre\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


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.