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CVE-2026-8337

MEDIUM 6.3

Published 2026-05-21 · Last modified 2026-05-22

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

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 9th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

6.3CVSS 4.0 · MEDIUM

  • ConfidentialityNone
  • IntegrityLow
  • AvailabilityNone

What an attacker needs

  • Access: Reachable over the network — no local access needed
  • Privileges: No account or privileges required
  • User interaction: No user interaction needed
  • Complexity: No special conditions — reliably repeatable
  • Requirements: Specific conditions must be present

✓ lowers the bar for an attacker · ⚠ raises it

Affected

Vendors Concrete Cms

Products Concrete Cms

Weakness (CWE)

  • CWE-639: Authorization bypass
  • CWE-565

CVSS 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

Sources: NVD · CVE.org · EPSS