CVE-2026-14574

5.7 MEDIUM 0.4% exploit odds Fix listed Other

What it is

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.

At a glance

Exploitability: Can be exploited locally on the machine without logging in, but needs a user to act. High risk of data tampering.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-08-05 11:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-23 21:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 5.7 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-08-05 11:16 UTC
Last modified: 2026-10-23 21:10 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-1321 · Prototype pollution
Record status: Analyzed

Affected

Eclipse Theia < 1.74.0

Attack profile CVSS 4.0 · 5.7

Attack vector: Local
Complexity: Low
Attack requirements: Present
Privileges needed: None
User interaction: Active
Confidentiality: Low
Integrity: High
Availability: Low

Raw 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-14574.md and follow it. Check whether this project is affected by CVE-2026-14574. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record