Quantum Secular Labs / Blog / Advisories

CVE-2026-47767: Sensiolabs Symfony: Interpretation Conflict

CVE-2026-47767 is rated critical with a CVSS v3.1 base score of 9.8 and affects Sensiolabs Symfony. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability 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.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
Attack complexity: Low. No special conditions; the attack can be repeated reliably.
Privileges required: None. No account or prior access is needed.
User interaction: None. No action from any user is needed.
Scope: Unchanged. Impact stays within the vulnerable component.
Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-436: Interpretation Conflict

Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.

Affected products

Sensiolabs 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