yii-starter-kit yii2-starter-kit up to 4.2.0 Attachment Download Endpoint improper authorization

Summaryinfo

A vulnerability labeled as problematic has been found in yii-starter-kit yii2-starter-kit up to 4.2.0. Affected by this vulnerability is an unknown functionality of the component Attachment Download Endpoint. Executing a manipulation can lead to improper authorization. The identification of this vulnerability is CVE-2026-103476. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in yii-starter-kit yii2-starter-kit up to 4.2.0. It has been declared as problematic. This vulnerability affects an unknown part of the component Attachment Download Endpoint. The manipulation with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect confidentiality. CVE summarizes:

yii2-starter-kit through 4.2.0 fails to validate article publication status in the attachment-download endpoint, allowing unauthenticated attackers to download files from draft articles. Attackers can enumerate sequential attachment identifiers to retrieve files from unpublished articles without authentication or authorization checks.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-103476 since 09/30/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/30/2026). The MITRE ATT&CK project declares the attack technique as T1548.002.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• yii-starter-kit

Name

• yii2-starter-kit

Version

• 4.0
• 4.1
• 4.2.0

Website

• Product: https://github.com/yii-starter-kit/yii2-starter-kit/

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