How severe is CVE-2026-47767?

No CVSS score has been assigned to CVE-2026-47767 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-47767?

CVE-2026-47767 affects the following packages: symfony/runtime (Packagist), symfony/runtime (Packagist), symfony/runtime (Packagist), symfony/runtime (Packagist), symfony/symfony (Packagist), symfony/symfony (Packagist), symfony/symfony (Packagist), symfony/symfony (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-47767?

Update symfony/runtime to 5.4.52 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-47767 is resolved across your whole dependency graph.

How do I detect CVE-2026-47767 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/runtime, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-47767 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-47767 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-47767 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-47767?

CVE-2026-47767 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 53th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-47767?

CVE-2026-47767 is classified as CWE-436 (CWE-436). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-47767 published, and has it been updated?

CVE-2026-47767 was published on July 14, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-47767 — runtime

Fix: symfony/symfony@3228c38

CVE-2026-47767 is a CWE-436 vulnerability in symfony/runtime. A fix is available for symfony/runtime — see the affected versions and patch details below.

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

Also known asGHSA-fqc7-9xjw-jrh3

Published

Jul 14, 2026

Updated

Aug 12, 2026

Affected

8 pkgs

Patched

8 / 8

Exploits

None indexed

Exploitation data as of Oct 12, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-47767.

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs53th percentile — riskier than 53% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

8 pkgs affected

🐘symfony/runtime🐘symfony/runtime🐘symfony/runtime🐘symfony/runtime🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

8 total 8 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`symfony/runtime`	≥ 5.4.46&&< 5.4.52	5.4.52`composer require symfony/runtime:^5.4.52`
🐘Packagist	`symfony/runtime`	≥ 6.4.14&&< 6.4.40	6.4.40`composer require symfony/runtime:^6.4.40`
🐘Packagist	`symfony/runtime`	≥ 7.1.7&&< 7.4.12	7.4.12`composer require symfony/runtime:^7.4.12`
🐘Packagist	`symfony/runtime`	≥ 8.0.0&&< 8.0.12	8.0.12`composer require symfony/runtime:^8.0.12`
🐘Packagist	`symfony/symfony`	≥ 5.4.46&&< 5.4.52	5.4.52`composer require symfony/symfony:^5.4.52`
🐘Packagist	`symfony/symfony`	≥ 6.4.14&&< 6.4.40	6.4.40`composer require symfony/symfony:^6.4.40`

Affected Products

1 product · 4 configurations

Application

symfonysensiolabs

≥ 8.0.0 && < 8.0.12

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/runtime, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update symfony/runtime to 5.4.52 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-47767 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### 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