TI-2026-10807 Aliases CVE-2026-12609 GHSA-34gw-v4cc-pv7c

Path traversal in Eclipse Theia

MEDIUM 42CWE-22Published 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
Confidentiality · integrity · availability: High · None · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-22 and the CVSS impact.

Summary

In Eclipse Theia versions 1.66.0 and up until including 1.73.1, the `@theia/plugin-ext` backend exposes the `/hostedPlugin/:pluginId/:path(*)` HTTP endpoint, which resolves the requested file path with `path.resolve(localPath, filePath)` without verifying that the resolved path stays within the plugin's directory. An unauthenticated network attacker can send percent-encoded `../` sequences (`%2e%2e%2f`) that decode into the path parameter and escape the plugin directory, allowing arbitrary files readable by the Theia backend process to be retrieved. Plugin IDs are derived deterministically from a plugin's publisher and name, so built-in plugins serve as reliable anchors that require no prior knowledge of the target system.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.01644 76th 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	1.66.0 to before 1.74.0	1.74.0	Patch available	CNA

Eclipse Theia VendorEclipse Foundation Affected 1.66.0 to 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::::::::	1.66.0 to before 1.74.0	Vulnerable	Eclipse Foundation

cpe:2.3:a:eclipse:theia:*:*:*:*:*:*:*:* Versions 1.66.0 to 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-2026-44283 Information disclosure in Eclipse TheiaPriority MEDIUM 40
- TI-2026-42788 Path traversal in Eclipse TheiaPriority MEDIUM 40
Show all 4 records →

Timeline

2026-10-02 Threatist record created from CVE-2026-12609
2026-10-03 Alias added: GHSA-34gw-v4cc-pv7c
2026-10-13 EPSS moved to the 50th–90th percentile
2026-10-13 Priority changed: LOW → MEDIUM

References

Advisory 2

Other 1

https://github.com/eclipse-theia/theia/security/advisories/GHSA-qmm6-p8q4-2g48

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-2026-44283 Information disclosure 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