Description
This is a residual bypass of CVE-2026-46635 / GHSA-vcc8-phrv-43wj that only affects sandboxing enabled through SourcePolicyInterface (and not the regular global sandbox mode).
CoreExtension::column() receives the active sandbox state via the needs_is_sandboxed channel as a boolean $isSandboxed, but then routes the per-element property reads through SandboxExtension::checkPropertyAllowed() without forwarding the current Source. SandboxExtension::checkPropertyAllowed() re-evaluates isSandboxed($source) internally; with $source = null the SourcePolicyInterface-driven decision is lost, the method short-circuits to "not sandboxed", and the property allowlist is never consulted.
A template author whose sandbox is gated by a SourcePolicyInterface and who has column on their allowedFilters list can therefore read any public or magic property of any object reachable in the render context, regardless of SecurityPolicy::$allowedProperties. Direct attribute access to the same property is blocked, and the same payload is also blocked under global sandbox mode, which makes this a clear policy enforcement gap rather than a configuration issue.
Resolution
CoreExtension::column() no longer goes through the SandboxExtension wrapper for the property check. It calls the security policy directly: the per-source decision is already captured by the $isSandboxed boolean computed at the call site, so the property allowlist is enforced consistently for both global and source-policy sandboxing.
Credits
Twig would like to thank Vincent55 Yang for reporting the issue and Fabien Potencier for providing the fix.
References
fabpot Remediation developer
Description
This is a residual bypass of CVE-2026-46635 / GHSA-vcc8-phrv-43wj that only affects sandboxing enabled through
SourcePolicyInterface(and not the regular global sandbox mode).CoreExtension::column()receives the active sandbox state via theneeds_is_sandboxedchannel as a boolean$isSandboxed, but then routes the per-element property reads throughSandboxExtension::checkPropertyAllowed()without forwarding the currentSource.SandboxExtension::checkPropertyAllowed()re-evaluatesisSandboxed($source)internally; with$source = nulltheSourcePolicyInterface-driven decision is lost, the method short-circuits to "not sandboxed", and the property allowlist is never consulted.A template author whose sandbox is gated by a
SourcePolicyInterfaceand who hascolumnon theirallowedFilterslist can therefore read any public or magic property of any object reachable in the render context, regardless ofSecurityPolicy::$allowedProperties. Direct attribute access to the same property is blocked, and the same payload is also blocked under global sandbox mode, which makes this a clear policy enforcement gap rather than a configuration issue.Resolution
CoreExtension::column()no longer goes through theSandboxExtensionwrapper for the property check. It calls the security policy directly: the per-source decision is already captured by the$isSandboxedboolean computed at the call site, so the property allowlist is enforced consistently for both global and source-policy sandboxing.Credits
Twig would like to thank Vincent55 Yang for reporting the issue and Fabien Potencier for providing the fix.
References