What is CVE-2026-47767?

CVE-2026-47767 is a medium-severity improper input validation vulnerability in symfony/runtime (composer), affecting versions >= 5.4.46, < 5.4.52. It is fixed in 5.4.52, 6.4.40, 7.4.12, 8.0.12. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.

Which packages are affected by CVE-2026-47767?

symfony/runtime (composer) versions >= 5.4.46, = 5.4.46, < 5.4.52.

Is there a fix for CVE-2026-47767?

Yes. CVE-2026-47767 is fixed in 5.4.52, 6.4.40, 7.4.12, 8.0.12. Upgrade to this version or later.

Is CVE-2026-47767 exploitable, and should I be worried?

Whether CVE-2026-47767 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2026-47767 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

CVE-2026-47767 in symfony/runtime

Q: Which packages are affected by CVE-2026-47767?

symfony/runtime (composer) versions >= 5.4.46, = 5.4.46, < 5.4.52.

Q: Is there a fix for CVE-2026-47767?

Yes. CVE-2026-47767 is fixed in 5.4.52, 6.4.40, 7.4.12, 8.0.12. Upgrade to this version or later.

Q: Is CVE-2026-47767 exploitable, and should I be worried?

Whether CVE-2026-47767 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2026-47767 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2026-47767?

Upgrade: symfony/runtime to 5.4.52 or later, symfony/runtime to 6.4.40 or later, symfony/runtime to 7.4.12 or later, symfony/runtime to 8.0.12 or later, symfony/symfony to 5.4.52 or later, symfony/symfony to 6.4.40 or later, symfony/symfony to 7.4.12 or later, symfony/symfony to 8.0.12 or later.

Summary

SymfonyRuntime CVE-2024-50340 Patch Bypass: Web Requests Can Still Set APPENV/APPDEBUG via parse_str/SAPI Argv Mismatch

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.

Impact

The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.

Affected versions

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)

Security releases

symfony/runtime → 5.4.52 (composer) symfony/runtime → 6.4.40 (composer) symfony/runtime → 7.4.12 (composer) symfony/runtime → 8.0.12 (composer) symfony/symfony → 5.4.52 (composer) symfony/symfony → 6.4.40 (composer) symfony/symfony → 7.4.12 (composer) symfony/symfony → 8.0.12 (composer)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Upgrade the following packages to resolve this vulnerability:

symfony/runtime to 5.4.52 or later; symfony/runtime to 6.4.40 or later; symfony/runtime to 7.4.12 or later; symfony/runtime to 8.0.12 or later; symfony/symfony to 5.4.52 or later; symfony/symfony to 6.4.40 or later; symfony/symfony to 7.4.12 or later; symfony/symfony to 8.0.12 or later

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is CVE-2026-47767? CVE-2026-47767 is a medium-severity improper input validation vulnerability in symfony/runtime (composer), affecting versions >= 5.4.46, < 5.4.52. It is fixed in 5.4.52, 6.4.40, 7.4.12, 8.0.12. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
Which packages are affected by CVE-2026-47767?
- symfony/runtime (composer) (versions >= 5.4.46, < 5.4.52)
- symfony/symfony (composer) (versions >= 5.4.46, < 5.4.52)
Is there a fix for CVE-2026-47767? Yes. CVE-2026-47767 is fixed in 5.4.52, 6.4.40, 7.4.12, 8.0.12. Upgrade to this version or later.
Is CVE-2026-47767 exploitable, and should I be worried? Whether CVE-2026-47767 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2026-47767 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2026-47767?
- Upgrade symfony/runtime to 5.4.52 or later
- Upgrade symfony/runtime to 6.4.40 or later
- Upgrade symfony/runtime to 7.4.12 or later
- Upgrade symfony/runtime to 8.0.12 or later
- Upgrade symfony/symfony to 5.4.52 or later
- Upgrade symfony/symfony to 6.4.40 or later
- Upgrade symfony/symfony to 7.4.12 or later
- Upgrade symfony/symfony to 8.0.12 or later

Other vulnerabilities in symfony/runtime

CVE-IDSeverityPackage summary

CVE-2024-50340Mediumsymfony/runtime: Symfony allows changing the environment through a query