{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-66843",
        "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "state": "PUBLISHED",
        "assignerShortName": "EEF",
        "dateReserved": "2026-08-06T09:00:01.259Z",
        "datePublished": "2026-08-06T14:48:20.513Z",
        "dateUpdated": "2026-08-19T11:51:46.161Z"
    },
    "containers": {
        "cna": {
            "affected": [
                {
                    "collectionURL": "https://repo.hex.pm",
                    "cpes": [
                        "cpe:2.3:a:rrrene:html_sanitize_ex:*:*:*:*:*:*:*:*"
                    ],
                    "defaultStatus": "unaffected",
                    "modules": [
                        "Elixir.HtmlSanitizeEx.Scrubber.HTML5",
                        "Elixir.HtmlSanitizeEx"
                    ],
                    "packageName": "html_sanitize_ex",
                    "packageURL": "pkg:hex/html_sanitize_ex",
                    "product": "html_sanitize_ex",
                    "programFiles": [
                        "lib/html_sanitize_ex/scrubber/html5.ex",
                        "lib/html_sanitize_ex.ex"
                    ],
                    "programRoutines": [
                        {
                            "name": "'Elixir.HtmlSanitizeEx.Scrubber.HTML5':scrub_attribute/2"
                        },
                        {
                            "name": "'Elixir.HtmlSanitizeEx.Scrubber.HTML5':sanitize/1"
                        },
                        {
                            "name": "'Elixir.HtmlSanitizeEx':html5/1"
                        }
                    ],
                    "repo": "https://github.com/rrrene/html_sanitize_ex",
                    "vendor": "rrrene",
                    "versions": [
                        {
                            "lessThan": "1.4.5",
                            "status": "affected",
                            "version": "0.3.1",
                            "versionType": "semver"
                        },
                        {
                            "lessThan": "1.5.3",
                            "status": "affected",
                            "version": "1.5.0-rc.0",
                            "versionType": "semver"
                        }
                    ]
                },
                {
                    "collectionURL": "https://github.com",
                    "cpes": [
                        "cpe:2.3:a:rrrene:html_sanitize_ex:*:*:*:*:*:*:*:*"
                    ],
                    "defaultStatus": "unaffected",
                    "modules": [
                        "Elixir.HtmlSanitizeEx.Scrubber.HTML5",
                        "Elixir.HtmlSanitizeEx"
                    ],
                    "packageName": "rrrene/html_sanitize_ex",
                    "packageURL": "pkg:github/rrrene/html_sanitize_ex",
                    "product": "html_sanitize_ex",
                    "programFiles": [
                        "lib/html_sanitize_ex/scrubber/html5.ex",
                        "lib/html_sanitize_ex.ex"
                    ],
                    "programRoutines": [
                        {
                            "name": "'Elixir.HtmlSanitizeEx.Scrubber.HTML5':scrub_attribute/2"
                        },
                        {
                            "name": "'Elixir.HtmlSanitizeEx.Scrubber.HTML5':sanitize/1"
                        },
                        {
                            "name": "'Elixir.HtmlSanitizeEx':html5/1"
                        }
                    ],
                    "repo": "https://github.com/rrrene/html_sanitize_ex",
                    "vendor": "rrrene",
                    "versions": [
                        {
                            "changes": [
                                {
                                    "at": "bec27fec4de99e40c68c4285a610e09e791a3eaf",
                                    "status": "unaffected"
                                },
                                {
                                    "at": "ce038aa1af5a960d50f8eb5d368cc57bb2b9a9f0",
                                    "status": "unaffected"
                                }
                            ],
                            "lessThan": "*",
                            "status": "affected",
                            "version": "8976d64ea0b77d26093a94a43ec48a3978e8d028",
                            "versionType": "git"
                        }
                    ]
                }
            ],
            "configurations": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "<p>Only <code>HtmlSanitizeEx.html5/1</code>, and custom scrubbers declared with <code>use HtmlSanitizeEx, extend: :html5</code>, allow the <code>object</code> element, and the sanitized output must be rendered to other users.</p>\n<p>Script execution in the host origin additionally requires the application to serve attacker-controlled HTML from a same-origin path, such as an uploads directory served as <code>text/html</code>.</p>"
                        },
                        {
                            "base64": false,
                            "type": "text/markdown",
                            "value": "Only `HtmlSanitizeEx.html5/1`, and custom scrubbers declared with `use HtmlSanitizeEx, extend: :html5`, allow the `object` element, and the sanitized output must be rendered to other users.\n\nScript execution in the host origin additionally requires the application to serve attacker-controlled HTML from a same-origin path, such as an uploads directory served as `text/html`."
                        }
                    ],
                    "value": "Only HtmlSanitizeEx.html5/1, and custom scrubbers declared with use HtmlSanitizeEx, extend: :html5, allow the object element, and the sanitized output must be rendered to other users.\n\nScript execution in the host origin additionally requires the application to serve attacker-controlled HTML from a same-origin path, such as an uploads directory served as text/html."
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "cpeMatch": [
                                {
                                    "criteria": "cpe:2.3:a:rrrene:html_sanitize_ex:*:*:*:*:*:*:*:*",
                                    "versionEndExcluding": "1.4.5",
                                    "versionStartIncluding": "0.3.1",
                                    "vulnerable": true
                                },
                                {
                                    "criteria": "cpe:2.3:a:rrrene:html_sanitize_ex:*:*:*:*:*:*:*:*",
                                    "versionEndExcluding": "1.5.3",
                                    "versionStartIncluding": "1.5.0-rc.0",
                                    "vulnerable": true
                                }
                            ],
                            "negate": false,
                            "operator": "OR"
                        }
                    ],
                    "operator": "AND"
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "type": "finder",
                    "value": "Peter Ullrich"
                },
                {
                    "lang": "en",
                    "type": "remediation developer",
                    "value": "René Föhring"
                },
                {
                    "lang": "en",
                    "type": "analyst",
                    "value": "Jonatan Männchen / EEF"
                }
            ],
            "descriptions": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "<p>Inclusion of Functionality from Untrusted Control Sphere vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to load a document of their choosing into a trusted page via the <code>data</code> attribute of an <code>&lt;object&gt;</code> element in sanitized HTML. <code>object</code> is the one URI-bearing element in <code>lib/html_sanitize_ex/scrubber/html5.ex</code> never registered through <code>allow_tag_with_uri_attributes/3</code>, and its only guard is a prefix match on lowercase <code>\"javascript:\"</code>, so mixed-case variants, <code>data:</code> URIs, protocol-relative URLs and same-origin paths all survive.</p>\n<p>This is not unconditional cross-site scripting. A <code>javascript:</code> URL does not execute through <code>&lt;object data&gt;</code> in current browsers, <code>data:</code> documents load in an opaque origin, and host-origin script execution additionally requires the application to serve attacker-controlled content from a same-origin path.</p>\n<p>This issue affects html_sanitize_ex: from 0.3.1 before 1.4.5 and from 1.5.0-rc.0 before 1.5.3.</p>"
                        },
                        {
                            "base64": false,
                            "type": "text/markdown",
                            "value": "Inclusion of Functionality from Untrusted Control Sphere vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to load a document of their choosing into a trusted page via the `data` attribute of an `<object>` element in sanitized HTML. `object` is the one URI-bearing element in `lib/html_sanitize_ex/scrubber/html5.ex` never registered through `allow_tag_with_uri_attributes/3`, and its only guard is a prefix match on lowercase `\"javascript:\"`, so mixed-case variants, `data:` URIs, protocol-relative URLs and same-origin paths all survive.\n\nThis is not unconditional cross-site scripting. A `javascript:` URL does not execute through `<object data>` in current browsers, `data:` documents load in an opaque origin, and host-origin script execution additionally requires the application to serve attacker-controlled content from a same-origin path.\n\nThis issue affects html_sanitize_ex: from 0.3.1 before 1.4.5 and from 1.5.0-rc.0 before 1.5.3."
                        }
                    ],
                    "value": "Inclusion of Functionality from Untrusted Control Sphere vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to load a document of their choosing into a trusted page via the data attribute of an <object> element in sanitized HTML. object is the one URI-bearing element in lib/html_sanitize_ex/scrubber/html5.ex never registered through allow_tag_with_uri_attributes/3, and its only guard is a prefix match on lowercase \"javascript:\", so mixed-case variants, data: URIs, protocol-relative URLs and same-origin paths all survive.\n\nThis is not unconditional cross-site scripting. A javascript: URL does not execute through <object data> in current browsers, data: documents load in an opaque origin, and host-origin script execution additionally requires the application to serve attacker-controlled content from a same-origin path.\n\nThis issue affects html_sanitize_ex: from 0.3.1 before 1.4.5 and from 1.5.0-rc.0 before 1.5.3."
                }
            ],
            "impacts": [
                {
                    "capecId": "CAPEC-175",
                    "descriptions": [
                        {
                            "lang": "en",
                            "value": "CAPEC-175 Code Inclusion"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV4_0": {
                        "Automatable": "NOT_DEFINED",
                        "Recovery": "NOT_DEFINED",
                        "Safety": "NOT_DEFINED",
                        "attackComplexity": "LOW",
                        "attackRequirements": "PRESENT",
                        "attackVector": "NETWORK",
                        "baseScore": 2.3,
                        "baseSeverity": "LOW",
                        "privilegesRequired": "NONE",
                        "providerUrgency": "NOT_DEFINED",
                        "subAvailabilityImpact": "NONE",
                        "subConfidentialityImpact": "LOW",
                        "subIntegrityImpact": "LOW",
                        "userInteraction": "PASSIVE",
                        "valueDensity": "NOT_DEFINED",
                        "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
                        "version": "4.0",
                        "vulnAvailabilityImpact": "NONE",
                        "vulnConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "NONE",
                        "vulnerabilityResponseEffort": "NOT_DEFINED"
                    },
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ]
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-829",
                            "description": "CWE-829 Inclusion of Functionality from Untrusted Control Sphere",
                            "lang": "en",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
                "shortName": "EEF",
                "dateUpdated": "2026-08-19T11:51:46.161Z"
            },
            "references": [
                {
                    "tags": [
                        "vendor-advisory",
                        "related"
                    ],
                    "url": "https://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-xmm9-jc22-rcgj"
                },
                {
                    "tags": [
                        "related"
                    ],
                    "url": "https://cna.erlef.org/cves/CVE-2026-66843.html"
                },
                {
                    "tags": [
                        "related"
                    ],
                    "url": "https://osv.dev/vulnerability/EEF-CVE-2026-66843"
                },
                {
                    "tags": [
                        "patch"
                    ],
                    "url": "https://github.com/rrrene/html_sanitize_ex/commit/bec27fec4de99e40c68c4285a610e09e791a3eaf"
                },
                {
                    "tags": [
                        "patch"
                    ],
                    "url": "https://github.com/rrrene/html_sanitize_ex/commit/ce038aa1af5a960d50f8eb5d368cc57bb2b9a9f0"
                }
            ],
            "source": {
                "discovery": "EXTERNAL"
            },
            "title": "html_sanitize_ex HTML5 scrubber keeps attacker-supplied `<object>` elements, allowing untrusted content embedding",
            "workarounds": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "<p>Sanitize with <code>basic_html/1</code>, <code>markdown_html/1</code> or <code>strip_tags/1</code>, none of which allow <code>object</code>, or define a custom scrubber that omits it.</p>\n<p>A Content-Security-Policy of <code>object-src 'none'</code> blocks an injected <code>&lt;object&gt;</code> from loading, and hosting user uploads on a separate origin removes the escalation path.</p>"
                        },
                        {
                            "base64": false,
                            "type": "text/markdown",
                            "value": "Sanitize with `basic_html/1`, `markdown_html/1` or `strip_tags/1`, none of which allow `object`, or define a custom scrubber that omits it.\n\nA Content-Security-Policy of `object-src 'none'` blocks an injected `<object>` from loading, and hosting user uploads on a separate origin removes the escalation path."
                        }
                    ],
                    "value": "Sanitize with basic_html/1, markdown_html/1 or strip_tags/1, none of which allow object, or define a custom scrubber that omits it.\n\nA Content-Security-Policy of object-src 'none' blocks an injected <object> from loading, and hosting user uploads on a separate origin removes the escalation path."
                }
            ]
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-08-06T15:40:41.682905Z",
                                "id": "CVE-2026-66843",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-08-06T15:40:50.570Z"
                }
            }
        ]
    }
}