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Fencer Vulns
high 8.8

CVE-2026-60009 json

In Eclipse Theia versions up to and including 1.73.1, the `@theia/filesystem` backend binds `POST /file-upload` in every filesystem-enabled…

published 2026-08-05 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-53326

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

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.

Patch / fix

  • Eclipse Foundation Eclipse Theia 1.74.0

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
3 mo ago

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • gitlab.eclipse.org https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/595 referenced PoC, tagged "exploit" by a source, unverified
  • gitlab.eclipse.org https://gitlab.eclipse.org/security/vulnerability-reports/-/issues/595 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • Eclipse Foundation Eclipse Theia

Classification

Weakness
  • CWE-352 Cross-Site Request Forgery
  • CWE-306 Missing Authentication for Critical Functionality
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-73 External Control of File Name or Path

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.