CVE-2026-103475 (CVSS 9.1)

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.

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CVSS v3.1 Score

9.1

CRITICAL

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

EPSS — Exploit Prediction

0.0040

Probability of exploitation

0.33%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-489 CWE-489

References

Other References

https://github.com/yii-starter-kit/yii2-starter-kit https://github.com/yii-starter-kit/yii2-starter-kit/blob/cc2c451e8c959c7300b04efea597706a38609f58/common/config/web.php#L21 https://github.com/yii-starter-kit/yii2-starter-kit/issues/797 https://www.vulncheck.com/advisories/yii2-starter-kit-through-4.2.0-debug-and-gii-module-exposure

Frequently Asked Questions

What is CVE-2026-103475? +

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. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2026-103475? +

CVE-2026-103475 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0040, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-103475? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-103475