# CVE-2026-45304

## Summary

- **CVE ID:** CVE-2026-45304
- **Severity:** HIGH
- **CVSS Score:** 8.7 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N)
- **CWE:** CWE-776
- **Published:** Jul 14, 2026
- **Last Modified:** Jul 14, 2026

## Description

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Yaml\Parser resolved YAML collection aliases recursively, allowing a small untrusted YAML input to expand into a multi-gigabyte structure and exhaust memory. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.

## Affected Products

- symfony — symfony (< 5.4.52)
- symfony — symfony (>= 6.0.0-BETA1, < 6.4.40)
- symfony — symfony (>= 7.0.0-BETA1, < 7.4.12)
- symfony — symfony (>= 8.0.0-BETA1, < 8.0.12)
- symfony — yaml (< 5.4.52)
- symfony — yaml (>= 6.0.0-BETA1, < 6.4.40)
- symfony — yaml (>= 7.0.0-BETA1, < 7.4.12)
- symfony — yaml (>= 8.0.0-BETA1, < 8.0.12)

## References

- [CNA](https://github.com/symfony/symfony/security/advisories/GHSA-4qpc-3hr4-r2p4)
- [CNA](https://github.com/symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970a)
- [CNA](https://github.com/symfony/symfony/releases/tag/v5.4.52)
- [CNA](https://github.com/symfony/symfony/releases/tag/v6.4.40)
- [CNA](https://github.com/symfony/symfony/releases/tag/v7.4.12)
- [CNA](https://github.com/symfony/symfony/releases/tag/v8.0.12)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.68%
- **EPSS Percentile:** 50.5

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._