CVE-2026-45304
Symfony: YAML Parser Exponential Memory Allocation via Recursive Collection-Alias Expansion ("Billion Laughs")
CVSS Score
0.0
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-776 |
| Vendor | symfony |
| Product | symfony |
| Published | Jul 14, 2026 |
| Last Updated | Jul 14, 2026 |
Stay Ahead of the Next One
Get instant alerts for symfony symfony
Be the first to know when new unknown vulnerabilities affecting symfony symfony are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
Affected Versions
symfony / symfony
< 5.4.52 >= 6.0.0-BETA1, < 6.4.40 >= 7.0.0-BETA1, < 7.4.12 >= 8.0.0-BETA1, < 8.0.12
symfony / yaml
< 5.4.52 >= 6.0.0-BETA1, < 6.4.40 >= 7.0.0-BETA1, < 7.4.12 >= 8.0.0-BETA1, < 8.0.12
References
github.com: https://github.com/symfony/symfony/security/advisories/GHSA-4qpc-3hr4-r2p4 github.com: https://github.com/symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970a github.com: https://github.com/symfony/symfony/releases/tag/v5.4.52 github.com: https://github.com/symfony/symfony/releases/tag/v6.4.40 github.com: https://github.com/symfony/symfony/releases/tag/v7.4.12 github.com: https://github.com/symfony/symfony/releases/tag/v8.0.12