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CVE-2026-47767: Symfony: SymfonyRuntime CVE-2024-50340 Patch Bypass: Web Requests Can Still Set APP_ENV/APP_DEBUG via parse_str/SAPI Argv Mismatch

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-14 · updated 2026-07-16
• Weakness: CWE-436

Description

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 5.4.46 until 5.4.52, 6.4.40, 7.4.12, and 8.0.12, the CVE-2024-50340 fix gated runtime argv parsing on empty($_GET), but parse_str() and the web SAPI can disagree, allowing a crafted query string to leave $_GET empty while $_SERVER['argv'] still carries attacker-controlled --env or --no-debug flags that change APP_ENV or APP_DEBUG. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.

Affected products

• symfony: from 5.4.46 before 5.4.52; from 6.4.14 before 6.4.40; from 7.1.7 before 7.4.12; from 8.0.0 before 8.0.12 — fixed in 5.4.52, 6.4.40, 7.4.12, 8.0.12

How to fix

Upgrade to a fixed version: symfony 5.4.52, 6.4.40, 7.4.12, 8.0.12. Check the vendor advisory for mitigations.

References

• https://github.com/symfony/symfony/commit/3228c3806ee511008bea19a95084d460b17e5d25
• https://github.com/symfony/symfony/releases/tag/v5.4.52
• https://github.com/symfony/symfony/releases/tag/v6.4.40
• https://github.com/symfony/symfony/releases/tag/v7.4.12
• https://github.com/symfony/symfony/releases/tag/v8.0.12
• https://github.com/symfony/symfony/security/advisories/GHSA-fqc7-9xjw-jrh3

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