CVE-2026-12609
HIGH 7.5EPSS 1.6%
In Eclipse Theia versions 1.66.0 and up until including 1.73.1, the `@theia/plugin-ext` backend exposes the `/hostedPlugin/:pluginId/:path(*)` HTTP endpoint, which resolves the requested file path with `path.resolve(localPath, filePath)` without verifying that the resolved path stays within the plugin's directory. An unauthenticated network attacker can send percent-encoded `../` sequences (`%2e%2e%2f`) that decode into the path parameter and escape the plugin directory, allowing arbitrary files readable by the Theia backend process to be retrieved. Plugin IDs are derived deterministically from a plugin's publisher and name, so built-in plugins serve as reliable anchors that require no prior knowledge of the target system.
- Affected
- Eclipse Foundation · Eclipse Theia
- CVSS v3.1 ECLIPSE
- 7.5 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - EPSS
- 1.64% chance of exploitation in the next 30 days, 76th percentile
- Nuclei
- high · CWE-22
- Published
- 2026-08-05
Nuclei templates (1)
Security advisories
- https://gitlab.eclipse.org/security/cve-assignment/-/work_items/133
- https://gitlab.eclipse.org/security/vulnerability-reports/-/issues/524