Denial of Service Vulnerability in Symfony PHP Framework
CVE-2026-45133

8.2HIGH

Key Information:

Vendor

Symfony

Status
Symfony
Vendor
CVE Published:
14 July 2026

What is CVE-2026-45133?

The Symfony PHP framework is vulnerable to a Denial of Service attack due to the inadequately limited recursion of deeply nested mappings or sequences when the parser processes attacker-controlled input. This oversight allows an attacker to craft a document that could exhaust the PHP stack, resulting in a crash of the worker process. The issue has been addressed in subsequent versions, making it crucial for users to upgrade to versions 5.4.52, 6.4.40, 7.4.12, or 8.0.12 to safeguard their applications.

Affected Version(s)

symfony < 5.4.52 < 5.4.52

symfony >= 6.0.0-BETA1, < 6.4.40 < 6.0.0-BETA1, 6.4.40

symfony >= 7.0.0-BETA1, < 7.4.12 < 7.0.0-BETA1, 7.4.12

References

https://github.com/symfony/symfony/security/advisories/GH...
x_refsource_CONFIRM
https://github.com/symfony/symfony/releases/tag/v5.4.52
x_refsource_MISC
https://github.com/symfony/symfony/releases/tag/v6.4.40
x_refsource_MISC

CVSS V4

Score:
8.2
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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