# CVE-2026-10055: Server-side request forgery in Eclipse Theia

> Remote attackers can exploit an unvalidated URL in Eclipse Theia to perform server-side requests and read internal responses, exposing sensitive backend data.

- **Severity:** High 8.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Jul 2026
- **Updated:** 6 Jul 2026
- **Also known as:** GHSA-2m57-xxmh-v696

## What is CVE-2026-10055?

CVE-2026-10055 is a high-severity server-side request forgery vulnerability in Eclipse Theia, published on 3 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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).

Weakness: CWE-918 (Server-Side Request Forgery), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-10055?


## How do I fix CVE-2026-10055?

No fix has been published for CVE-2026-10055 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-10055 being exploited?

There is no known exploitation of CVE-2026-10055 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-10055 and fix it if it is affected.

What it is: CVE-2026-10055 is a high-severity server-side request forgery vulnerability in Eclipse Theia, published on 3 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-10055 in the wild and no public exploit code.

Affected product: Eclipse Theia. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-10055/ (Markdown: https://insights.sbomify.com/CVE-2026-10055/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-10055
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-10055
- OSV: https://osv.dev/vulnerability/CVE-2026-10055

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-10055/
Summaries are generated and may contain mistakes; the official description above is the record.