In Eclipse Theia versions up to and including 1.2.0, the Markdown Preview (@theia/preview), can be exploited to execute arbitrary code.
https://omespino.com/write-up-google-bug-bounty-xss-to-cloud-shell-instance-takeover-rce-as-root-5000-usd/
https://github.com/eclipse-theia/theia/issues/7954
Source: Mitre, NVD
Published: 2021-02-24
Updated: 2026-06-17
Base Score: 9.3
Vector: CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C
Severity: High
Base Score: 9.6
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Severity: Critical
EPSS: 0.00531