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CVE-2026-8204

6.3 mediumEPSS 0.2%

Medium (6.3) in concretecms concrete cms. EPSS 0.2% chance of exploitation in the next 30 days.

Concrete CMS 9.5.0 and below is vulnerable to authorization Bypass in the Calendar Event Frontend Dialog which can allow cross-calendar data disclosure. A public calendar block can be used as a pivot point to access private calendar data. 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:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.

Severity

CVSS 4.0

6.3 medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

5.3 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS
0.2% chance of exploitation in the next 30 days; higher than 11% of CVEs (scores of 2026-10-31)
CWE
CWE-639
Published
Modified
Record from
the NVD, synced

Affected

References

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