What’s Vulnerable › Vulnerabilities

CVE-2020-5274: Exceptions displayed in non-debug configurations in Symfony

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-03-30 · updated 2026-06-17
• Weakness: CWE-209

Description

In Symfony before versions 5.0.5 and 4.4.5, some properties of the Exception were not properly escaped when the `ErrorHandler` rendered it stacktrace. In addition, the stacktrace were displayed even in a non-debug configuration. The ErrorHandler now escape alls properties of the exception, and the stacktrace is only display in debug configuration. This issue is patched in symfony/http-foundation versions 4.4.5 and 5.0.5

Affected products

• symfony: from 4.4.0 before 4.4.4; from 5.0.0 before 5.0.4 — fixed in 4.4.4, 5.0.4

How to fix

Upgrade to a fixed version: symfony 4.4.4, 5.0.4. Check the vendor advisory for mitigations.

References

• https://github.com/symfony/symfony/commit/629d21b800a15dc649fb0ae9ed7cd9211e7e45db
• https://github.com/symfony/symfony/commit/cf80224589ac05402d4f72f5ddf80900ec94d5ad
• https://github.com/symfony/symfony/security/advisories/GHSA-m884-279h-32v2
• https://github.com/symfony/symfony/commit/629d21b800a15dc649fb0ae9ed7cd9211e7e45db
• https://github.com/symfony/symfony/commit/cf80224589ac05402d4f72f5ddf80900ec94d5ad
• https://github.com/symfony/symfony/security/advisories/GHSA-m884-279h-32v2

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