CVE-2026-61891

In Eclipse Theia versions up to and including 1.73.1, the `@theia/filesystem` backend exposes HTTP file-download endpoints (`GET /file`, `GET /files/`, `PUT /files/`) that convert a client-supplied URI directly to a filesystem path and stream the file, without confining it to the workspace or any allow-listed root. 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, so these endpoints are reachable without a valid token. As a result an unauthenticated client can read any file readable by the backend process, including files outside the opened workspace (for example `/etc/hosts`, SSH keys, or tokens). Electron mode uses a separate `ElectronSecurityToken` and is not affected via this path.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/eclipse-theia/theia/security/advisories/GHSA-qqc8-9538-25v4	Broken Link
https://gitlab.eclipse.org/security/cve-assignment/-/work_items/176	Vendor Advisory
https://gitlab.eclipse.org/security/vulnerability-reports/-/issues/570	Issue Tracking Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:eclipse:theia:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-08-05 12:18

Updated : 2026-08-07 15:48

NVD link : CVE-2026-61891

Mitre link : CVE-2026-61891

CVE.ORG link : CVE-2026-61891

JSON object : View

Products Affected

eclipse

theia

CWE

CWE-22

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CWE-36

Absolute Path Traversal

CWE-200

Exposure of Sensitive Information to an Unauthorized Actor

CWE-306

Missing Authentication for Critical Function

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