CVE-2026-10055: eclipse foundation eclipse theia

Vulnerability summary

CVE-2026-10055 is a high (CVSS 8.5) vulnerability in eclipse foundation eclipse theia. EPSS estimates a 0.40% chance of exploitation in the next 30 days, higher than 32.6% of scored vulnerabilities.

Timeline

1. 03-07-2026
   PublishedVulnerability first disclosed.
2. 06-07-2026
   Last modifiedVulnerability information updated.

Description

In Eclipse Theia since version 1.26.0, the backend /services/request-service RPC accepts an attacker-controlled URL from any client connected to the standard /services messaging endpoint, performs the HTTP request server-side, and returns the full response body to the caller. Because the destination URL is neither validated nor allowlisted, a remote attacker with access to the Theia service connection can issue server-side HTTP requests to localhost or other backend-reachable hosts and read their responses, exposing internal administrative endpoints, cloud instance metadata services, and other resources that are intentionally outside the browser network boundary. The vulnerability affects deployments where the Theia service connection is reachable by untrusted users (for example, multi-tenant or publicly-reachable Theia deployments).

• CWE-200Exposure of Sensitive Information to an Unauthorized ActorThe product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
• CWE-918Server-Side Request Forgery (SSRF)The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.