What is CVE-2021-28661?

CVE-2021-28661 is a medium-severity vulnerability in Silverstripe, classified under Incorrect Authorization. CVSS score: 4.3/10. Published 2021-10-07.

How severe is CVE-2021-28661?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Auth bypass in Silverstripe

CVE-2021-28661

Default SilverStripe GraphQL Server (aka silverstripe/graphql) 3.x through 3.4.1 permission checker not inherited by query subclass.

Vulnerability class: Broken Access Control

Published 2021-10-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.008 (55.3th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 55.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Silverstripe

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

github.com/silverstripe/silverstripe-graphql/releases (Third Party Advisory, Release Notes)
www.silverstripe.org/download/security-releases/CVE-2021-28661 (Exploit, Vendor Advisory)

Frequently asked questions

What is CVE-2021-28661?: CVE-2021-28661 is a medium-severity vulnerability in Silverstripe, classified under Incorrect Authorization. CVSS score: 4.3/10. Published 2021-10-07.
How severe is CVE-2021-28661?: Medium severity. CVSS v3 base score is 4.3 out of 10.