What is CVE-2020-27224?

CVE-2020-27224 is a critical-severity vulnerability in Eclipse Theia, classified under Cross-site Scripting. CVSS score: 9.6/10. Published 2021-02-24.

How severe is CVE-2020-27224?

Critical severity. CVSS v3 base score is 9.6 out of 10.

XSS in Eclipse Theia

CVE-2020-27224

In Eclipse Theia versions up to and including 1.2.0, the Markdown Preview (@theia/preview), can be exploited to execute arbitrary code.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-02-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.6 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.026 (84.7th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 85th percentile — 84.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.024 · newest: 0.026 · change: +0.002

Affected products

Eclipse Theia
The Eclipse Foundation Theia — versions unspecified

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/eclipse-theia/theia/issues/7954 (Exploit, Third Party Advisory, Issue Tracking)
omespino.com/write-up-google-bug-bounty-xss-to-cloud-shell-instance-takeover-rc… (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2020-27224?: CVE-2020-27224 is a critical-severity vulnerability in Eclipse Theia, classified under Cross-site Scripting. CVSS score: 9.6/10. Published 2021-02-24.
How severe is CVE-2020-27224?: Critical severity. CVSS v3 base score is 9.6 out of 10.