CVE-2026-82217: eclipse foundation eclipse theia Path Traversal

Vulnerability summary

CVE-2026-82217 is a high (CVSS 8.8) Path Traversal vulnerability in eclipse foundation eclipse theia. EPSS estimates a 0.62% chance of exploitation in the next 30 days, higher than 48.5% of scored vulnerabilities.

Timeline

1. 31-08-2026
   PublishedVulnerability first disclosed.
2. 01-09-2026
   Last modifiedVulnerability information updated.

Description

In Eclipse Theia versions 1.73.0 up to but not including 1.75.0, the AI "Agent Mode" file-change tools (writeFileContent, suggestFileContent, and the replacement and state helpers) resolved a model-supplied file path without a workspace-containment check. A crafted relative path such as ../.bashrc, an absolute path, or a ~-expanded path could therefore write or delete files outside the workspace with the privileges of the Theia backend OS user. Because the path argument is influenced by model output, it can be steered through indirect prompt injection, and in Agent Mode writes are applied without a confirmation dialog. Writing to a host-executed file such as a shell startup file or ~/.ssh/authorized_keys can escalate to code execution on the backend.

• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.