CVE-2026-8337

Concrete CMS 9.5.0 and below is vulnerable to IDOR in surveys when sites are running concurrent public surveys and private surveys

State: Published
Severity: 6.3 Medium
Published: May 21, 2026
Updated: May 22, 2026
Reserved: May 11, 2026

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Description

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

Scores

CVSS	Score	Vector	Source
4.0	6.3 Medium	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	ConcreteCMS

Weaknesses

CWE-639 Authorization bypass through User-Controlled key
CWE-565 Reliance on cookies without validation and integrity checking

Affected Products

Product	Versions
Concrete CMSConcrete CMS	5.0 through 9.5.0Affected

References

https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notesrelease-notes

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