EUVD-2026-64046Severity by source
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network-delivered via homeserver with no privileges required, but passive user interaction needed to load the homepage; CSP limits impact to low confidentiality and integrity with no code execution.
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
Lifecycle Timeline
3DescriptionCVE.org
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.
AnalysisAI
Element Web's EmbeddedPage component rendered homeserver-supplied homepage HTML directly into the DOM via React's dangerouslySetInnerHTML without first passing it through the application's sanitizedHtmlNode utility, enabling any malicious or compromised Matrix homeserver to inject arbitrary HTML into the client homepage of connecting users prior to version 1.12.22. The Content Security Policy blocks JavaScript execution, constraining impact to HTML-based phishing - fake login forms, spoofed UI overlays - rather than remote code execution. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to control or have compromised the specific Matrix homeserver that the victim's Element Web instance is configured to use - this vulnerability is not exploitable by arbitrary network attackers against default configurations of independent deployments. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N) scoring 5.3 Medium accurately reflects the constrained impact profile: network-delivered, low complexity, but limited to low confidentiality and integrity impact with no availability consequence. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade Element Web to version 1.12.22 or later, confirmed available at https://github.com/element-hq/element-web/releases/tag/v1.12.22. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-79 – Cross-site Scripting (XSS)
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External POC / Exploit Code
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