Vulnerability · Published Sep 30, 2026 · Assigned by VulnCheck

CVE-2026-103476yii2-starter-kit through 4.2.0 Unauthorized File Download via attachment-download

Medium 5.3

In plain English

A medium-severity authorization bypass via user-controlled key 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 0.3% (higher than 22% of all known vulnerabilities).

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.3%top 78.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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 Attackers can enumerate sequential attachment identifiers to retrieve files from unpublished articles without authentication or authorization checks.

Affected products (as reported)

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

Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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/frontend/controllers/ArticleController.php#L69 technical-description
VulnCheck Advisory: yii2-starter-kit through 4.2.0 Unauthorized File Download via attachment-download third-party-advisory