Medium Injection exploit reference

CVE-2026-14574 — Prototype Pollution in Eclipse Foundation Theia

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.

Published Aug 5, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: eclipse

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (medium)+3
CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Eclipse Foundation

Theia

CVSS base

6.5

Medium · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

Proof of concept

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented mitigation — gitlab.eclipse.org (NIST National Vulnerability Database)
Documented mitigation — gitlab.eclipse.org (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Eclipse Foundation Theia).
Apply the documented mitigations until a definitive fix is available.
Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Eclipse Foundation	Theia	≥ 0.7.0 and < 1.74.0	Vulnerable	NIST National Vulnerability Database
Eclipse Foundation	Theia	≥ 0.7.0 and < 1.74.0	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
5.7	CVSS 4.0	Medium	—	—	emo@eclipse.org via NIST National Vulnerability Database
5.7	CVSS 4.0	Medium	—	—	eclipse via CVE Program (cve.org) e CISA ADP
6.5	CVSS 3.1	Medium	2.8	3.6	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-1321 · Prototype Pollution

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Look for parameters with command/query metacharacters and unexpected child processes of the service.

web/proxy/WAF logsnetwork IDS/IPSapplication logsendpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · eclipse foundation/eclipse theia
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
Fix documented
Oct 15, 2026 · NIST National Vulnerability Database
CVSS changed · 6.5
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Aug 5, 2026 · eclipse

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

4 on the record

gitlab.eclipse.org/security/cve-assignment/-/work_items/157
Vendor Advisory, NIST National Vulnerability Database
gitlab.eclipse.org/security/vulnerability-reports/-/work_items/567
Exploit, Mitigation, Vendor Advisory, NIST National Vulnerability Database
gitlab.eclipse.org/security/vulnerability-reports/-/issues/567
Exploit, Mitigation, Vendor Advisory, Issue Tracking, NIST National Vulnerability Database
github.com/eclipse-theia/theia/security/advisories/GHSA-f3w9-qfw3-xr32
Broken Link, NIST National Vulnerability Database

Elsewhere on this site

Eclipse Foundation
every CVE for this vendor

Injection
same class

CWE-1321
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-82217 Path Traversal in Eclipse Foundation Theia Aug 31, 2026
High CVE-2026-19884 In Eclipse Theia versions up to and including 1.69.0, opening a folder starts source… Aug 14, 2026
High CVE-2026-61891 Path Traversal in Eclipse Foundation Theia Aug 5, 2026
High CVE-2026-60009 Path Traversal in Eclipse Foundation Theia Aug 5, 2026
High CVE-2026-12609 Path Traversal in Eclipse Foundation Theia Aug 5, 2026
High CVE-2026-10055 Exposure of Sensitive Information in Eclipse Foundation Theia Jul 3, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-14574 is "Prototype Pollution in Eclipse Foundation Theia", rated Medium. It affects Theia (Eclipse Foundation); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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