---
cve: "CVE-2026-12609"
severity: "HIGH"
cvss: 7.5
epss: "41%"
vendor: "Eclipse Foundation"
kev: false
exploited: false
published: "2026-08-05 11:16:24"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-14T03:21:02+02:00"
---

# CVE-2026-12609

> 7.5 HIGH · 🧪 PoC

## Beschreibung

In Eclipse Theia versions 1.66.0 and up until including 1.73.1, the `@theia/plugin-ext` backend exposes the `/hostedPlugin/:pluginId/:path(*)` HTTP endpoint, which resolves the requested file path with `path.resolve(localPath, filePath)` without verifying that the resolved path stays within the plugin's directory. An unauthenticated network attacker can send percent-encoded `../` sequences (`%2e%2e%2f`) that decode into the path parameter and escape the plugin directory, allowing arbitrary files readable by the Theia backend process to be retrieved. Plugin IDs are derived deterministically from a plugin's publisher and name, so built-in plugins serve as reliable anchors that require no prior knowledge of the target system.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Keine | good |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- 172494ea2564ca07690e230805861146007fae79 (Commit)

## Referenzen

- <https://github.com/eclipse-theia/theia/security/advisories/GHSA-qmm6-p8q4-2g48>
- <https://gitlab.eclipse.org/security/vulnerability-reports/-/issues/524>
- <https://gitlab.eclipse.org/security/cve-assignment/-/work_items/133>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-12609) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_