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.
History

Wed, 05 Aug 2026 13:30:00 +0000

Type Values Removed Values Added
References
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 05 Aug 2026 13:15:00 +0000

Type Values Removed Values Added
Title Prototype Pollution via Preference Merge in Eclipse Theia Settings

Wed, 05 Aug 2026 12:45:00 +0000

Type Values Removed Values Added
First Time appeared Eclipse
Eclipse theia
Vendors & Products Eclipse
Eclipse theia

Wed, 05 Aug 2026 11:15:00 +0000

Type Values Removed Values Added
Description 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.
Weaknesses CWE-1321
References
Metrics cvssV4_0

{'score': 5.7, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:L/VI:H/VA:L/SC:N/SI:L/SA:L'}


cve-icon MITRE

Status: PUBLISHED

Assigner: eclipse

Published: 2026-08-05T10:51:47.869Z

Updated: 2026-08-05T13:05:29.371Z

Reserved: 2026-07-03T11:09:54.712Z

Link: CVE-2026-14574

cve-icon Vulnrichment

Updated: 2026-08-05T13:05:25.814Z

cve-icon NVD

No data.

cve-icon Redhat

No data.