# CVE-2020-7747: Cross-site Scripting (XSS)

> An attacker can inject malicious JavaScript into the lightning-server session controller, potentially executing code in the victim's browser.

- **Severity:** Medium 6.3 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N/E:P/RL:U/RC:C`)
- **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:** 20 Oct 2020
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-gmch-cm2p-9qw9

## What is CVE-2020-7747?

CVE-2020-7747 is a medium-severity cross-site scripting vulnerability in lightning-server, published on 20 Oct 2020. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

This affects all versions of package lightning-server. It is possible to inject malicious JavaScript code as part of a session controller.

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

## Which versions are affected by CVE-2020-7747?

2 open source packages ship an affected version, including lightning-server. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `lightning-server` | npm | All versions to 1.3.0 | None |
| `lightning-server` | npm | All versions to 1.3.0 | None |

Products: Lightning-Viz Lightning.

## How do I fix CVE-2020-7747?

No fix has been published for CVE-2020-7747 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-7747 being exploited?

There is no known exploitation of CVE-2020-7747 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-7747 and fix it if it is affected.

What it is: CVE-2020-7747 is a medium-severity cross-site scripting vulnerability in lightning-server, published on 20 Oct 2020. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-7747 in the wild and no public exploit code.

Affected packages and fixed versions:
- lightning-server (npm): affected all versions up to 1.3.0; no fix listed
- lightning-server (npm): affected all versions up to 1.3.0; no fix listed

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-2020-7747/ (Markdown: https://insights.sbomify.com/CVE-2020-7747/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-7747
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-7747
- OSV: https://osv.dev/vulnerability/CVE-2020-7747

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-7747/
Summaries are generated and may contain mistakes; the official description above is the record.