Vulnerability · Published Aug 21, 2026 · Assigned by GitHub_M

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

Medium 5.3

In plain English

A medium-severity cross-site scripting in element-web from element-hq. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities).

Severity (CVSS 4.0)5.3Medium

Exploit odds (30 days)0.5%top 54.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
element-hq	element-web	< 1.12.22

Weakness: CWE-79 · Vector: 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

References

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