{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-55850",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-06-17T16:44:40.994Z",
        "datePublished": "2026-08-21T18:30:12.251Z",
        "dateUpdated": "2026-08-21T19:54:55.604Z"
    },
    "containers": {
        "cna": {
            "title": "Element Web: A malicious homeserver can inject HTML in Element Web using its homepage",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-79",
                            "lang": "en",
                            "description": "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV4_0": {
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "attackRequirements": "NONE",
                        "privilegesRequired": "NONE",
                        "userInteraction": "PASSIVE",
                        "vulnConfidentialityImpact": "LOW",
                        "vulnIntegrityImpact": "LOW",
                        "vulnAvailabilityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "subIntegrityImpact": "NONE",
                        "subAvailabilityImpact": "NONE",
                        "baseScore": 5.3,
                        "baseSeverity": "MEDIUM",
                        "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
                        "version": "4.0"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/element-hq/element-web/security/advisories/GHSA-wrcp-5v3v-3j6v",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/element-hq/element-web/security/advisories/GHSA-wrcp-5v3v-3j6v"
                },
                {
                    "name": "https://github.com/element-hq/element-web/commit/7949980a7e3c7e397d7afe899ef1b0563c417b0e",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/element-hq/element-web/commit/7949980a7e3c7e397d7afe899ef1b0563c417b0e"
                },
                {
                    "name": "https://github.com/element-hq/element-web/releases/tag/v1.12.22",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/element-hq/element-web/releases/tag/v1.12.22"
                },
                {
                    "name": "https://www.machinespirits.com/advisory/563a17",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://www.machinespirits.com/advisory/563a17"
                }
            ],
            "affected": [
                {
                    "vendor": "element-hq",
                    "product": "element-web",
                    "versions": [
                        {
                            "version": "< 1.12.22",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-08-21T18:30:12.251Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Element Web is a Matrix web client built using the Matrix React SDK. Prior to 1.12.22, EmbeddedPage in apps/web/src/components/structures/EmbeddedPage.tsx renders homeserver-supplied homepage content through dangerouslySetInnerHTML without passing it through sanitizedHtmlNode. A malicious homeserver can provide crafted HTML that Element Web renders on the homepage; the content security policy prevents JavaScript but not phishing HTML. This issue is fixed in version 1.12.22."
                }
            ],
            "source": {
                "advisory": "GHSA-wrcp-5v3v-3j6v",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-08-21T19:54:43.766385Z",
                                "id": "CVE-2026-55850",
                                "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": "2026-08-21T19:54:55.604Z"
                }
            }
        ]
    }
}