# CVE-2019-18888: Argument injection in a MimeTypeGuesser in Symfony

Source: https://junglewise.ai/threats/cve-2019-18888-argument-injection-in-a-mimetypeguesser-in-symfony  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2019-12-02  
License: CC BY 4.0 with a link back

CVE-2019-18888 · Severity: low · CVSS 3.1 · Published 2019-12-02

Argument injection in a MimeTypeGuesser in Symfony

Technologies: [symfony/http-foundation (Packagist)](https://junglewise.ai/threats/technologies/symfony-http-foundation), [symfony/mime (Packagist)](https://junglewise.ai/threats/technologies/symfony-mime), [symfony/symfony (Packagist)](https://junglewise.ai/threats/technologies/symfony-symfony). Vendors: [Packagist](https://junglewise.ai/threats/vendors/packagist).

## Quick answers

**Is CVE-2019-18888 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2019-18888 being exploited in the wild.

**How severe is CVE-2019-18888?** Low severity, with a CVSS score of 3.1, published 2 December 2019.

**Which products and versions are affected?** symfony/http-foundation (Packagist) ECOSYSTEM:introduced=2.0.0,fixed=2.8.52; symfony/mime (Packagist) ECOSYSTEM:introduced=4.3.0,fixed=4.3.8; symfony/symfony (Packagist) ECOSYSTEM:introduced=2.0.0,fixed=2.8.52.

**Is there a fix for CVE-2019-18888?** Yes. symfony/http-foundation (Packagist): upgrade to 2.8.52 or later; symfony/mime (Packagist): upgrade to 4.3.8 or later; symfony/symfony (Packagist): upgrade to 2.8.52 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2019-18888?** Check whether you run symfony/http-foundation (Packagist), symfony/mime (Packagist) or symfony/symfony (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- symfony/http-foundation (Packagist): upgrade to 2.8.52 or later

  ```sh
  composer require symfony/http-foundation:^2.8.52
  ```

- symfony/mime (Packagist): upgrade to 4.3.8 or later

  ```sh
  composer require symfony/mime:^4.3.8
  ```

- symfony/symfony (Packagist): upgrade to 2.8.52 or later

  ```sh
  composer require symfony/symfony:^2.8.52
  ```


## Affected products

- symfony/http-foundation (Packagist) ECOSYSTEM:introduced=2.0.0,fixed=2.8.52
- symfony/mime (Packagist) ECOSYSTEM:introduced=4.3.0,fixed=4.3.8
- symfony/symfony (Packagist) ECOSYSTEM:introduced=2.0.0,fixed=2.8.52

## Identifiers

- CVE-2019-18888
- GHSA-xhh6-956q-4q69

## Related threats

- [Symfony YAML stack exhaustion in inline lexer](https://junglewise.ai/threats/cve-2026-109413-in-symfony-yaml-prior-to-versions-5-4-54-6-4-45-7-4-18-and-8-1-6)
- [Symfony HTTP Foundation ReDoS in HeaderUtils::split()](https://junglewise.ai/threats/cve-2026-108082-symfony-is-a-php-framework-for-web-and-console-applications-and)
- [Symfony Routing improper dot-segment encoding in UrlGenerator](https://junglewise.ai/threats/cve-2026-48784-symfony-routing-improper-dot-segment-encoding-in-urlgenerator)
- [Symfony HtmlSanitizer XSS via incomplete URL attribute sanitization](https://junglewise.ai/threats/cve-2026-48761-symfony-htmlsanitizer-xss-via-incomplete-url-attribute)
- [Symfony HtmlSanitizer visual spoofing via percent-encoded BiDi characters](https://junglewise.ai/threats/cve-2026-48760-symfony-htmlsanitizer-visual-spoofing-via-percent-encoded-bidi)