Vulnerability · Published Sep 30, 2026 · Assigned by VulnCheck

CVE-2026-103475yii2-starter-kit through 4.2.0 Debug and Gii Module Exposure

Critical 9.1

In plain English

A critical-severity security flaw in yii2-starter-kit from yii2-starter-kit. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities).

Severity (CVSS 3.1)9.1Critical

Exploit odds (30 days)0.4%top 65.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

yii2-starter-kit through 4.2.0 exposes the Yii debug and Gii modules to all IP addresses by setting allowedIPs to ['*'] in its default development configuration. Unauthenticated remote attackers can access the debug endpoint to read sensitive data including session cookies and database queries, or access the Gii endpoint to generate and write PHP files into the application directory.

Affected products (as reported)

Vendor	Product	Versions
yii2-starter-kit	yii2-starter-kit	0 – through 4.2.0

Weakness: CWE-489 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References

GitHub Issue #797 issue-tracking
https://github.com/yii-starter-kit/yii2-starter-kit product
https://github.com/yii-starter-kit/yii2-starter-kit/blob/cc2c451e8c959c7300b04efea597706a38609f58/common/config/web.php#L21 technical-description
VulnCheck Advisory: yii2-starter-kit through 4.2.0 Debug and Gii Module Exposure third-party-advisory