Exceptions displayed in non-debug configurations in Symfony
Description
When ErrorHandler renders an exception HTML page, it uses un-escaped properties from the related Exception class to render the stacktrace. The security issue comes from the fact that the stacktraces were also displayed in non-debug environments.
Resolution
The ErrorHandler class now escapes all properties coming from the related Exception, and the stacktrace is not displayed anymore in non-debug environments.
The patches for this issue are available here and here for branch 4.4.
Credits
I would like to thank Luka Sikic for reporting & Yonel Ceruto and Jérémy Derussé for fixing the issue.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | symfony/error-handler | >= 4.4.0, < 4.4.4, >= 5.0.0, < 5.0.4 | 4.4.4, 5.0.4 |
| Composer package | symfony/symfony | >= 4.4.0, < 4.4.4, >= 5.0.0, < 5.0.4 | 4.4.4, 5.0.4 |
References
- https://github.com/symfony/symfony/security/advisories/GHSA-m884-279h-32v2
- https://nvd.nist.gov/vuln/detail/CVE-2020-5274
- https://github.com/symfony/symfony/commit/629d21b800a15dc649fb0ae9ed7cd9211e7e45db
- https://github.com/symfony/symfony/commit/cf80224589ac05402d4f72f5ddf80900ec94d5ad
- https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/error-handler/CVE-2020-5274.yaml
- https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2020-5274.yaml
- https://symfony.com/cve-2020-5274
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N- Weakness (CWE)
CWE-209- Platform
- Composer
- Package
symfony/error-handler, symfony/symfony- Disclosed
- 30.03.2020
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-m884-279h-32v2 - CC BY 4.0
Vulnerability history: symfony/error-handler
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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