CVE-2021-34435

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-09-01 · updated 2026-06-17
Weakness: CWE-942

Description

In Eclipse Theia 0.3.9 to 1.8.1, the "mini-browser" extension allows a user to preview HTML files in an iframe inside the IDE. But with the way it is made it is possible for a previewed HTML file to trigger an RCE. This exploit only happens if a user previews a malicious file..

Affected products

Eclipse Foundation Eclipse Theia: from 0.3.9 through 1.8.1

References

https://bugs.eclipse.org/bugs/show_bug.cgi?id=568018
https://bugs.eclipse.org/bugs/show_bug.cgi?id=568018

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