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GHSA-fqc7-9xjw-jrh3
No affected components available
Description
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 $_SERVER['argv'] carries the attacker's flags. SymfonyRuntime::getInput() then parses them, restoring the exact primitive CVE-2024-50340 was meant to prevent.
Preconditions and impact match the original CVE: web SAPI, register_argc_argv=On, app booted through symfony/runtime; from an unauthenticated GET an attacker can flip APP_ENV and toggle APP_DEBUG.
Resolution
SymfonyRuntime now gates the argv read on isset($_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.
Credits
SymfonyRuntime would like to thank 0xEr3n for reporting the issue and Nicolas Grekas for providing the fix.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability.
Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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