CVE-2026-8337

Concrete CMS 9.5.0 and below is vulnerable to IDOR in surveys. To be vulnerable, a site would have to be configured in such a way that both public and private surveys are present on the site. An unauthenticated attacker can vote in the restricted survey by submitting the restricted optionID through the public survey’s endpoint. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks  Zer0daySec https://github.com/Zee99y  for reporting

Affected products

Concrete Cms

Concretecms Concrete Cms

< 9.5.1

Fix

Available

CVSS 4.0

6.3 MEDIUM

CVSS 3.1

5.3 MEDIUM

EPSS

0.2% (9th percentile)

Weakness

CWE-639, CWE-565

NVD status

Analyzed

Published

2026-05-21

Attack patterns

CAPEC-31, CAPEC-1