TI-2026-44283 Aliases CVE-2026-61891 GHSA-xrrm-6636-87r2

Information disclosure in Eclipse Theia

MEDIUM 40CWE-200Published 2026-08-05 · Updated 2026-08-05

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Information disclosure, Security bypass
Confidentiality · integrity · availability: High · None · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-200 and CWE-306.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00533 45th percentileScored 2026-11-07

Fix Fixed Eclipse Theia (Eclipse Foundation): 1.74.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Eclipse Foundation	Eclipse Theia	before 1.74.0	1.74.0	Patch available	CNA

Eclipse Theia VendorEclipse Foundation Affected before 1.74.0 Fixed in 1.74.0 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:eclipse:theia::::::::	before 1.74.0	Vulnerable	Eclipse Foundation

cpe:2.3:a:eclipse:theia:*:*:*:*:*:*:*:* Versions before 1.74.0 Vulnerable ·Eclipse Foundation

Remediation

Fix · CNA Eclipse Theia (Eclipse Foundation) Fixed in 1.74.0

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-08-05
Eclipse Theia 1.74.0
4 records Highest priority Priority MEDIUM 4 MEDIUM
Other records, highest priority first
- TI-2026-12294 Prototype pollution in Eclipse TheiaPriority MEDIUM 59
- TI-2026-10807 Path traversal in Eclipse TheiaPriority MEDIUM 42
- TI-2026-42788 Path traversal in Eclipse TheiaPriority MEDIUM 40
Show all 4 records →

Timeline

2026-10-02 Threatist record created from CVE-2026-61891
2026-10-03 Alias added: GHSA-xrrm-6636-87r2

References

Advisory 2

Other 1

https://github.com/eclipse-theia/theia/security/advisories/GHSA-qqc8-9538-25v4

TI-2026-12294 Prototype pollution in Eclipse Theia CVSS 4.0MEDIUM 5.7
TI-2021-13470 Path traversal in Eclipse Theia CVSS 3.1CRITICAL 9.8
TI-2020-16550 Cross-site scripting in Eclipse Theia CVSS 3.1CRITICAL 9.6
TI-2026-10807 Path traversal in Eclipse Theia CVSS 3.1HIGH 7.5
TI-2026-42788 Path traversal in Eclipse Theia CVSS 3.1HIGH 8.8
TI-2026-34242 In Eclipse Theia versions prior to 1.71.0, files matching the pattern… CVSS 4.0HIGH 8.4

See all 14 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences