CSRF in Eclipse Theia
CVE-2026-60009
In Eclipse Theia versions up to and including 1.73.1, the `@theia/filesystem` backend binds `POST /file-upload` in every filesystem-enabled deployment. The handler takes an attacker-supplied absolute path from the multipart `uri` field and calls `fs.move(tmp, target, { overwrite: true })` with no workspace confinement and no authentication. In browser (non-Electron) deployments the connection token is enforced only on WebSocket upgrades; the HTTP middleware in `@theia/core` re-issues the cookie and calls `next()` without rejecting tokenless HTTP requests. Because `multipart/form-data` is a CORS-safelisted request type, a cross-origin web page can trigger the write with no preflight and no credentials, resulting in an unauthenticated arbitrary file write outside the workspace to any absolute path the backend process can write. This can escalate to remote code execution, for example by overwriting a startup-executed file such as `~/.bashrc`. Electron mode uses a separate `ElectronSecurityToken` and is not affected via this path.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (38.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 38.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Eclipse Theia
- Eclipse Foundation Theia — versions 0
Weakness classification (CWE)
References
- github.com/eclipse-theia/theia/security/advisories/GHSA-62f6-wcvg-54h3 (Broken Link)
- gitlab.eclipse.org/security/cve-assignment/-/work_items/177 (Vendor Advisory)
- gitlab.eclipse.org/security/vulnerability-reports/-/issues/595 (Exploit, Mitigation, Vendor Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Exploit, Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-60009?
- CVE-2026-60009 is a high-severity vulnerability in Eclipse Theia, classified under Path Traversal. CVSS score: 8.8/10. Published 2026-08-05.
- How severe is CVE-2026-60009?
- High severity. CVSS v3 base score is 8.8 out of 10.