CVE-2021-34436: Eclipse Theia

Critical severity, CVSS 9.8. EPSS: 2.2% chance of exploitation in the next 30 days.

In Eclipse Theia 0.1.1 to 0.2.0, it is possible to exploit the default build to obtain remote code execution (and XXE) via the theia-xml-extension. This extension uses lsp4xml (recently renamed to LemMinX) in order to provide language support for XML. This is installed by default.

Affected products

• Eclipse Theia: from 0.1.1, up to and including 0.2.0

Published 2021-09-02. Last modified 2026-06-17.