# CVE-2017-18343: Cross-site scripting in n/a

> Cross-site scripting in Symfony debug handler allows code execution via array keys during exception printing, affecting developers using debug tools.

- **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:** Yes
- **Published:** 20 Jul 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2017-18343, GHSA-mm4c-ww47-3x4c

## What is CVE-2017-18343?

CVE-2017-18343 is a medium-severity cross-site scripting vulnerability in Sensiolabs Symfony, published on 20 Jul 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

The debug handler in Symfony before v2.7.33, 2.8.x before v2.8.26, 3.x before v3.2.13, and 3.3.x before v3.3.6 has XSS via an array key during exception pretty printing in ExceptionHandler.php, as demonstrated by a /_debugbar/open?op=get URI. NOTE: the vendor's position is that this is not a vulnerability because the debug tools are not intended for production use. NOTE: the Symfony Debug component is used by Laravel Debugbar

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

## Which versions are affected by CVE-2017-18343?

It affects 1 product.


Products: Sensiolabs Symfony.

## How do I fix CVE-2017-18343?

Upgrade to a fixed version.

## Is CVE-2017-18343 being exploited?

There is no known exploitation of CVE-2017-18343 in the wild and no public exploit code.

## Other vulnerabilities in Sensiolabs Symfony

- [CVE-2019-11325](https://insights.sbomify.com/CVE-2019-11325/): Improper Input Validation in Symfony (critical 9.8)
- [CVE-2017-11365](https://insights.sbomify.com/CVE-2017-11365/): Symfony Incorrect Access Control (critical 9.8)
- [CVE-2019-10913](https://insights.sbomify.com/CVE-2019-10913/): Invalid HTTP method overrides allow possible XSS or other attacks in Symfony (critical 9.8)
- [CVE-2018-11407](https://insights.sbomify.com/CVE-2018-11407/): Symfony Authentication Bypass (critical 9.8)
- [CVE-2016-2403](https://insights.sbomify.com/CVE-2016-2403/): Symfony Authentication Bypass (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-18343 and fix it if it is affected.

What it is: CVE-2017-18343 is a medium-severity cross-site scripting vulnerability in Sensiolabs Symfony, published on 20 Jul 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-2017-18343 in the wild and no public exploit code.

Affected product: Sensiolabs Symfony. 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-2017-18343/ (Markdown: https://insights.sbomify.com/CVE-2017-18343/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-18343
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-18343
- OSV: https://osv.dev/vulnerability/CVE-2017-18343

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-18343/
Summaries are generated and may contain mistakes; the official description above is the record.