Is CVE-2026-8337 in the CISA KEV catalog?

No. CVE-2026-8337 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-8337?

CVE-2026-8337 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-8337?

CVE-2026-8337 has an EPSS score of 0.19% (9th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-8337?

Upgrade concrete cms to 9.5.1 or later.

CVE & CISA-KEV Catalog

CVE-2026-8337

MEDIUM

5.3

CVSS v3

NVD

Description

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

CWE-565 CWE-639Authorization Bypass Through User-Controlled Key

How to fix

Remediation Available

concrete cmsNVD

Affected:< 9.5.1Fixed in:9.5.1CVE-2026-8337derived 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

ConfidentialityNone

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

0.19%probability of exploitation in 30 days

9thpercentile

Low risk: more likely to be exploited than 9% of all known CVEs.

References

Release Notes1

documentation.concretecms.org

Embed a live status badge for CVE-2026-8337

Markdown

[![CVE-2026-8337](https://tridentstack.com/cve/badge/CVE-2026-8337.svg)](https://tridentstack.com/cve/CVE-2026-8337)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-8337"><img src="https://tridentstack.com/cve/badge/CVE-2026-8337.svg" alt="CVE-2026-8337"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

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.