Is CVE-2026-8205 in the CISA KEV catalog?

No. CVE-2026-8205 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-8205?

CVE-2026-8205 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-8205?

CVE-2026-8205 has an EPSS score of 0.21% (11th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2026-8205?

No published fix for CVE-2026-8205 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

CVE & CISA-KEV Catalog

CVE-2026-8205

MEDIUM

5.3

CVSS v3

NVD

Description

Concrete CMS 9.5.0 and below is vulnerable to authorization bypass in the Calendar Block since action_get_events does not check canView on the calendar which results in restricted event details being disclosed. 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 lalalala5678 for reporting.

CWE-425

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Exploit Intelligence

0.21%probability of exploitation in 30 days

11thpercentile

Low risk: more likely to be exploited than 11% of all known CVEs.

References

Release Notes1

documentation.concretecms.org

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-26.