# CVE-2018-11101: Cross-site scripting in n/a

> Attackers can execute arbitrary JavaScript in Signal Desktop by sending crafted HTML messages and replying to them, potentially leading to full system compromise.

- **Severity:** Medium 6.1 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 17 May 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-hf9p-487c-2v2r

## What is CVE-2018-11101?

CVE-2018-11101 is a medium-severity cross-site scripting vulnerability in n/a, published on 17 May 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Open Whisper Signal (aka Signal-Desktop) through 1.10.1 allows XSS via a resource location specified in an attribute of a SCRIPT, IFRAME, or IMG element, leading to JavaScript execution after a reply, a different vulnerability than CVE-2018-10994. The attacker needs to send HTML code directly as a message, and then reply to that message to trigger this vulnerability. The Signal-Desktop software fails to sanitize specific HTML elements that can be used to inject HTML code into remote chat windows when replying to an HTML message. Specifically the IMG and IFRAME elements can be used to include remote or local resources. For example, the use of an IFRAME element enables full code execution, allowing an attacker to download/upload files, information, etc. The SCRIPT element was also found to be injectable. On the Windows operating system, the CSP fails to prevent remote inclusion of resources via the SMB protocol. In this case, remote execution of JavaScript can be achieved by referencing the script on an SMB share within an IFRAME element, for example: <IFRAME src=\\DESKTOP-XXXXX\Temp\test.html> and then replying to it. The included JavaScript code is then executed automatically, without any interaction needed from the user. The vulnerability can be triggered in the Signal-Desktop client by sending a specially crafted message and then replying to it with any text or content in the reply (it doesn't matter).

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

## Which versions are affected by CVE-2018-11101?

It affects 1 product.


Products: Signal Signal-Desktop.

## How do I fix CVE-2018-11101?

No fix has been published for CVE-2018-11101 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-11101 being exploited?

There is no known exploitation of CVE-2018-11101 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2023-24068](https://insights.sbomify.com/CVE-2023-24068/): Missing authorization in n/a (high 7.8)
- [CVE-2019-19954](https://insights.sbomify.com/CVE-2019-19954/): Privilege escalation in n/a (high 7.3)
- [CVE-2018-10994](https://insights.sbomify.com/CVE-2018-10994/): Cross-site scripting in n/a (medium 6.1)
- [CVE-2018-14023](https://insights.sbomify.com/CVE-2018-14023/): Information disclosure in n/a (medium 4.0)
- [CVE-2023-24069](https://insights.sbomify.com/CVE-2023-24069/): Information disclosure in n/a (low 3.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-11101 and fix it if it is affected.

What it is: CVE-2018-11101 is a medium-severity cross-site scripting vulnerability in n/a, published on 17 May 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-11101 in the wild and no public exploit code.

Affected product: n/a. 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-2018-11101/ (Markdown: https://insights.sbomify.com/CVE-2018-11101/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-11101
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-11101
- OSV: https://osv.dev/vulnerability/CVE-2018-11101

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-11101/
Summaries are generated and may contain mistakes; the official description above is the record.