CVE-2026-12609 (GCVE-0-2026-12609)
Vulnerability from cvelistv5 – Published: 2026-08-05 10:55 – Updated: 2026-08-05 13:03
VLAI
EPSS
VEX
Summary
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.
Severity
7.5 (High)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-05 13:03 UTC
CWE
Assigner
eclipse
CNA
References
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Eclipse Foundation | Eclipse Theia |
Affected:
1.66.0 , < 1.74.0
(semver)
|
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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