TI-2026-12294 Aliases CVE-2026-14574 GHSA-5f8h-2xph-wwxv

Prototype pollution in Eclipse Theia

MEDIUM 59CWE-1321Published 2026-08-05 · Updated 2026-08-05

Key facts

Attack vector: Local
Privileges required: None
User interaction: Active
Attack complexity: Low
Attack requirements: Present
Impact type: —
Confidentiality · integrity · availability: Low · High · Low
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

In Eclipse Theia versions 0.7.0 and up until including 1.73.1, the `PreferenceUtils.merge` function in `@theia/core` recursively merges preference values without rejecting prototype-related keys (`__proto__`, `constructor`, `prototype`). Because this function is invoked by `PreferenceServiceImpl.doResolve` for every preference resolution across scopes (default, user, workspace, folder), a crafted preference value in a workspace settings file (`.theia/settings.json` or `.vscode/settings.json`) can pollute `Object.prototype` when the user opens the workspace, potentially altering application logic across the Theia process.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00395 33rd percentileScored 2026-11-07

Public exploit Yes 2 exploit referencesTagged by NVD

Fix Fixed Eclipse Theia (Eclipse Foundation): 1.74.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
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	0.7.0 to before 1.74.0	1.74.0	Patch available	CNA

Eclipse Theia VendorEclipse Foundation Affected 0.7.0 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::::::::	0.7.0 to before 1.74.0	Vulnerable	Eclipse Foundation

cpe:2.3:a:eclipse:theia:*:*:*:*:*:*:*:* Versions 0.7.0 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-2026-10807 Path traversal in Eclipse TheiaPriority MEDIUM 42
- 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-2026-14574
2026-10-03 Alias added: GHSA-5f8h-2xph-wwxv

References

Exploit 2

Advisory 1

https://gitlab.eclipse.org/security/cve-assignment/-/work_items/157

Other 1

https://github.com/eclipse-theia/theia/security/advisories/GHSA-f3w9-qfw3-xr32

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-2026-44283 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