CVE-2024-50340 (GHSA-x8vp-gf4q-mw5j) addressed an issue where, with register_argc_argv=On, a crafted query string let an unauthenticated GET change the kernel environment and debug flag by feeding --env/--no-debug through $_SERVER['argv']. The fix shipped in symfony/runtime 5.4.46 / 6.4.14 / 7.1.7 gated the argv read on empty($_GET) as a proxy for "is this a CLI invocation".
That proxy is unsafe: parse_str() (which builds $_GET) and the web SAPI (which builds $_SERVER['argv'] from the raw query when register_argc_argv=On) do not agree on every input, so an attacker can craft a query that leaves $_GET empty while $_SERVER['argv'] carries the attacker's flags. SymfonyRuntime::getInput() then parses them, restoring the exact primitive CVE-2024-50340 was meant to prevent.
Preconditions and impact match the original CVE: web SAPI, register_argc_argv=On, app booted through symfony/runtime; from an unauthenticated GET an attacker can flip APP_ENV and toggle APP_DEBUG.
SymfonyRuntime now gates the argv read on isset($_SERVER['QUERY_STRING']) rather than on empty($_GET). QUERY_STRING is the same input the SAPI uses to build argv, so the security check and the thing it protects no longer parse different sources. Worker SAPIs (FrankenPHP / RoadRunner / Swoole) keep working because the runtime constructor runs once at boot when QUERY_STRING is unset.
The patch for this issue is available here for branch 5.4.
SymfonyRuntime would like to thank 0xEr3n for reporting the issue and Nicolas Grekas for providing the fix.
| Software | From | Fixed in |
|---|---|---|
symfony / runtime
|
5.4.46 | 5.4.52 |
symfony / runtime
|
6.4.14 | 6.4.40 |
symfony / runtime
|
7.1.7 | 7.4.12 |
symfony / runtime
|
8.0.0 | 8.0.12 |
symfony / symfony
|
5.4.46 | 5.4.52 |
symfony / symfony
|
6.4.14 | 6.4.40 |
symfony / symfony
|
7.1.7 | 7.4.12 |
symfony / symfony
|
8.0.0 | 8.0.12 |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.