Missing Origin Validation in WebSockets in Eclipse Theia - CVE-2026-10054
Published: July 22, 2026
Vulnerability identifier: #VU139169
CSH Severity: High
CVSS v4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-10054
CWE-ID: CWE-1385
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary commands and read their output.
The vulnerability exists due to missing origin validation in WebSocket terminal RPC services when handling cross-origin WebSocket connections. A remote attacker can lure a victim into visiting a malicious webpage that connects to the terminal service and issues crafted terminal RPC requests to execute arbitrary commands and read their output.
User interaction is required to visit a malicious webpage, and the issue affects browser-based deployments where the backend WebSocket is reachable.
Affected software
Eclipse Theia
How to mitigate CVE-2026-10054
Install security update from vendor's website.
Eclipse Theia - update to 1.73.0