CVE-2026-39850 remediation guide
yiisoft yii2
Yii 2 is a PHP application framework. Versions 2.0.54 and prior contain flawed logic in the core view rendering method View::renderPhpFile() that leads to Local File Inclusion. The function calls extract($_params_, EXTR_OVERWRITE) before the require statement that loads the view file. As a result, a caller-controlled _file_ key in the $params array overwrites the internal local variable specifying which file to include, potentially enabling RCE if an attacker can write PHP files through a separate primitive, as well as information disclosure. This issue has been fixed in version 2.0.55.
A verified fixed-version field is not available. Use the linked NVD and supporting references, then confirm the vendor-supported path before changing production systems.
Identify the affected asset
Confirm whether yiisoft yii2 is installed, record the deployed version and installation path, and identify exposed interfaces.
- Record the product name, package or appliance identifier, and installed version.
- Identify internet-facing, administrative, API, and internal access paths.
- Preserve the pre-change configuration and relevant service logs.
Validate the affected-version match
Compare the deployed version with the affected range: >= < 2.0.55. Treat incomplete inventory results as unresolved.
Prioritize with independent signals
The CVSS severity warrants an early asset and exposure review. Combine this signal with asset criticality, exposure, compensating controls, and business impact.
Apply supported remediation
Follow the vendor advisory or supported update path. Current fixed-version status: No verified fixed-version field is available yet. Preserve configuration and rollback material before change.
Verify the result
Confirm the resulting version, service health, authentication and access paths, monitoring coverage, and relevant security logs.
- Confirm the expected version and package state.
- Run a functional health check for critical service paths.
- Review authentication, error, application, and security monitoring logs.
- Reassess exposure if the supported fix cannot be applied.
Operational boundary
This page does not replace the vendor advisory, support contract, change-management process, or recovery plan. Do not infer that an asset is unaffected from an incomplete inventory query or a missing fixed-version field.