Medium severity5.3NVD Advisory· Published May 21, 2026· Updated May 26, 2026
CVE-2026-8204
CVE-2026-8204
Description
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
concrete5/concrete5Packagist | < 9.5.1 | 9.5.1 |
Affected products
4Patches
Vulnerability mechanics
References
3- github.com/advisories/GHSA-x2fp-hj8c-mmxhghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-8204ghsaADVISORY
- documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notesnvdRelease NotesWEB
News mentions
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