CVE•Published 2026-05-21•Modified 2026-05-26•0 articles on news•6 live references•NVD data

CVE-2026-8337Concretecms · Concrete_cms

Vulnerability data via NVD (ingested)

CVSS v3.1

5.3

MEDIUM

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

EPSS percentile

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Weaknesses (CWE)

CWE-565Reliance on Cookies without Validation and Integrity Checking CWE-639Authorization Bypass Through User-Controlled Key

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

Timeline

Published 2026-05-21

Modified 2026-05-26

External references

NVD MITRE Exploit-DB GitHub PoC Sploitus VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-8337

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Concretecms Concrete Cms"

All exposed Concretecms Concrete Cms instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Concrete Cms"

HTTP body or banner mentions "Concrete Cms" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-8337