# CVE-2026-53711: MCP ContextForge: Global Prompts stored cross-site scripting compromises the Admin UI

> An authenticated attacker can inject malicious scripts into Global Prompts, leading to session hijacking and data theft when other users view the Admin UI.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 13 Oct 2026
- **Updated:** 13 Oct 2026
- **Also known as:** GHSA-x6gc-rm5j-55mw

## What is CVE-2026-53711?

CVE-2026-53711 is a medium-severity cross-site scripting vulnerability in IBM mcp-context-forge, published on 13 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

MCP Context Forge provides an MCP Admin UI for managing gateway resources. From 0.2.0 until 0.3.1, the Global Prompts feature stores a prompt template without sufficient output encoding before the MCP Admin UI renders it. An authenticated attacker can save markup containing script-capable event handlers, and the code executes when another user views the saved prompt. The stored cross-site scripting can alter the interface, present phishing content, observe keystrokes available to the page, and act with the viewer's browser session. This issue is fixed in version 0.3.1.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-53711?


## How do I fix CVE-2026-53711?

No fix has been published for CVE-2026-53711 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-53711 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53711 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53711 and fix it if it is affected.

What it is: CVE-2026-53711 is a medium-severity cross-site scripting vulnerability in IBM mcp-context-forge, published on 13 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53711 exists.

Affected product: IBM mcp-context-forge. 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-2026-53711/ (Markdown: https://insights.sbomify.com/CVE-2026-53711/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53711
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53711
- OSV: https://osv.dev/vulnerability/CVE-2026-53711

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-53711/
Summaries are generated and may contain mistakes; the official description above is the record.