CVE-2026-45133
High
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, when the parser is exposed to attacker-controlled input, deeply nested mappings or sequences cause both the block-level (Parser::parseBlock()) and inline (Inline::parseSequence() / Inline::parseMapping()) parsers to recurse without a depth limit. A crafted document exhausts the PHP stack and crashes the worker. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
SeverityHigh
CVSS7.5
Exploit probability50. percentile0.6%
Product
Sensiolabs Symfony
PublishedJul 14, 2026
First seenJul 14, 2026
Weakness typeCWE-674CWE-674CWE-776CWE-776CWE-1333CWE-1333
How to fix
Update
- sensiolabs symfony5.4.52, 6.4.40, 7.4.12, 8.0.12 or later
- symfony/yaml5.4.52, 6.4.40, 7.4.12, 8.0.12 or later
- symfony/symfony5.4.52, 6.4.40, 7.4.12, 8.0.12 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| sensiolabs symfony | v < 5.4.52, 6.0.0 ≤ v < 6.4.40, 7.0.0 ≤ v < 7.4.12, 8.0.0 ≤ v < 8.0.12 | 5.4.52, 6.4.40, 7.4.12, 8.0.12 |
| symfony/yamlPackagist | v < 5.4.52, 6.0.0 ≤ v < 6.4.40, 7.0.0 ≤ v < 7.4.12, 8.0.0 ≤ v < 8.0.12 | 5.4.52, 6.4.40, 7.4.12, 8.0.12 |
| symfony/symfonyPackagist | v < 5.4.52, 6.0.0 ≤ v < 6.4.40, 7.0.0 ≤ v < 7.4.12, 8.0.0 ≤ v < 8.0.12 | 5.4.52, 6.4.40, 7.4.12, 8.0.12 |
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