CVE-2026-39850 Yii 2: Local file inclusion via view parameter name collision
Attackers can exploit a variable collision in Yii 2's view rendering to include arbitrary local files, potentially leading to remote code execution or information disclosure.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-39850?
CVE-2026-39850 is a high-severity path traversal vulnerability in yiisoft yii2, published on 20 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-39850?
2 open source packages ship an affected version, including yiisoft/yii2.
| Package | Affected | Fixed in |
|---|---|---|
yiisoft/yii2 Packagist | All versions | 2.0.55 |
yiisoft/yii2 Packagist | All versions | 2.0.55 |
How do I fix CVE-2026-39850?
Upgrade yiisoft/yii2 to 2.0.55 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-39850 being exploited?
There is no known exploitation of CVE-2026-39850 in the wild and no public exploit code.
Sources
Also known as CLSA-2026-1787002033, GHSA-5vpg-rj7q-qpw2.