Auth bypass in @Studiocms S3-Storage
CVE-2026-32101
StudioCMS is a server-side-rendered, Astro native, headless content management system. Prior to 0.3.1, the S3 storage manager's isAuthorized() function is declared async (returns Promise<boolean>) but is called without await in both the POST and PUT handlers. Since a Promise object is always truthy in JavaScript, !isAuthorized(type) always evaluates to false, completely bypassing the authorization check. Any authenticated user with the lowest visitor role can upload, delete, rename, and list all files in the S3 bucket. This vulnerability is fixed in 0.3.1.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L.
EPSS exploit prediction
EPSS: 0.003 (18.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 18.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- @Studiocms S3-Storage — versions < 0.3.1
- Studiocms
Weakness classification (CWE)
References
- github.com/withstudiocms/studiocms/security/advisories/GHSA-mm78-fgq8-6pgr (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-32101?
- CVE-2026-32101 is a high-severity vulnerability in @Studiocms S3-Storage, classified under Incorrect Authorization. CVSS score: 7.6/10. Published 2026-03-11.
- How severe is CVE-2026-32101?
- High severity. CVSS v3 base score is 7.6 out of 10.