CVE-2026-14574
Eclipse Theia Prototype Pollution Vulnerability
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.
INFO
Published Date :
Aug. 5, 2026, 11:16 a.m.
Last Modified :
Aug. 7, 2026, 4:02 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | e51fbebd-6053-4e49-959f-1b94eeb69a2c | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Eclipse Theia to version 1.74.0 or later.
- Review and sanitize preference file inputs.
- Avoid recursive merging of untrusted preference data.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-14574.
| URL | Resource |
|---|---|
| https://github.com/eclipse-theia/theia/security/advisories/GHSA-f3w9-qfw3-xr32 | Broken Link |
| https://gitlab.eclipse.org/security/cve-assignment/-/work_items/157 | Vendor Advisory |
| https://gitlab.eclipse.org/security/vulnerability-reports/-/issues/567 | Exploit Mitigation Vendor Advisory Issue Tracking |
| https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/567 | Exploit Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-14574 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-14574
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-14574 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-14574 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Aug. 07, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N Added CPE Configuration OR *cpe:2.3:a:eclipse:theia:*:*:*:*:*:*:*:* versions from (including) 0.7.0 up to (excluding) 1.74.0 Added Reference Type Eclipse Foundation: https://github.com/eclipse-theia/theia/security/advisories/GHSA-f3w9-qfw3-xr32 Types: Broken Link Added Reference Type Eclipse Foundation: https://gitlab.eclipse.org/security/cve-assignment/-/work_items/157 Types: Vendor Advisory Added Reference Type Eclipse Foundation: https://gitlab.eclipse.org/security/vulnerability-reports/-/issues/567 Types: Exploit, Issue Tracking, Mitigation, Vendor Advisory Added Reference Type CISA-ADP: https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/567 Types: Exploit, Mitigation, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 05, 2026
Action Type Old Value New Value Added Reference https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/567 Added SSVC {'id': 'CVE-2026-14574', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-05T13:04:59.354596Z'} -
New CVE Received by [email protected]
Aug. 05, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Eclipse Foundation', 'product': 'Eclipse Theia', 'versions': [{'status': 'affected', 'version': '0.7.0', 'lessThan': '1.74.0', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] 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. Added CVSS V4.0 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 Added CWE CWE-1321 Added Reference https://github.com/eclipse-theia/theia/security/advisories/GHSA-f3w9-qfw3-xr32 Added Reference https://gitlab.eclipse.org/security/cve-assignment/-/work_items/157 Added Reference https://gitlab.eclipse.org/security/vulnerability-reports/-/issues/567