Prototype Pollution in Eclipse Theia PreferenceUtils.merge (0.7-1.73.1)
CVE-2026-14574 Published on August 5, 2026
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.
Vulnerability Analysis
CVE-2026-14574 is exploitable with local system access. This vulnerability is considered to have a low attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2026-14574. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
What is a Prototype Pollution Vulnerability?
The software receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
CVE-2026-14574 has been classified to as a Prototype Pollution vulnerability or weakness.
Products Associated with CVE-2026-14574
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Affected Versions
Eclipse Foundation Eclipse Theia:- Version 0.7.0 and below 1.74.0 is affected.