What’s Vulnerable › Vulnerabilities

CVE-2026-55850: Element Web: A malicious homeserver can inject HTML in Element Web using its homepage

• Severity: medium (CVSS 5.3 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-21 · updated 2026-10-14
• Weakness: CWE-79

Description

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.

Affected products

• element-hq element-web: before 1.12.22

References

• https://github.com/element-hq/element-web/commit/7949980a7e3c7e397d7afe899ef1b0563c417b0e
• https://github.com/element-hq/element-web/releases/tag/v1.12.22
• https://github.com/element-hq/element-web/security/advisories/GHSA-wrcp-5v3v-3j6v
• https://www.machinespirits.com/advisory/563a17

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