CVE-2021-34436

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-09-02 · updated 2026-06-17
Weakness: CWE-22

Description

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 Foundation Eclipse Theia: from 0.1.1 through 0.2.0

References

https://bugs.eclipse.org/bugs/show_bug.cgi?id=563174
https://bugs.eclipse.org/bugs/show_bug.cgi?id=563174

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