Is CVE-2026-8237 in the CISA KEV catalog?

No. CVE-2026-8237 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-8237?

CVE-2026-8237 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-8237?

CVE-2026-8237 has an EPSS score of 0.20% (10th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-8237?

Upgrade concrete cms to 9.5.1 or later.

CVE & CISA-KEV Catalog

CVE-2026-8237

MEDIUM

5.3

CVSS v3

NVD

Description

Concrete CMS 9.5.0 and below is vulnerable to IDOR. The `/ccm/frontend/conversations/message_detail` endpoint returns the full content of any conversation message. An unauthenticated attacker can enumerate all conversation messages, including messages from restricted pages, member-only areas, and the moderation queue. File attachments with download URLs are also exposed. 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 Eldudareeno for reporting.

CWE-862Missing Authorization

How to fix

Remediation Available

concrete cmsNVD

Affected:< 9.5.1Fixed in:9.5.1CVE-2026-8237derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

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

0.20%probability of exploitation in 30 days

10thpercentile

Low risk: more likely to be exploited than 10% of all known CVEs.

References

Release Notes1

documentation.concretecms.org

Related Vulnerabilities

Other CWE-862 (Missing Authorization) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2021-39226	Critical	9.8	100%	KEV	Fix
CVE-2022-0543	Critical	10.0	100%	KEV	Fix
CVE-2021-21978	Critical	9.8	99%	-	Fix
CVE-2023-52163	High	8.8	96%	KEV	-
CVE-2022-1329	High	8.8	93%	-	-
CVE-2023-6875	Critical	9.8	90%	-	-

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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.