CVE-2026-8337mediumCWE-565CWE-639

CVE-2026-8337: medium-severity vulnerability in Concrete CMS

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

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33Vexday Risk Score

No sign of exploitation. It has a public proof of concept.

ssvc Attendcvss 6.3epss 0.2%
from disclosure to weapon71 days
Published on NVDMay 21
1st PoC+71d
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
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
Affected products
Concrete CMS · Concrete CMS
⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
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