How severe is CVE-2026-8240?

CVE-2026-8240 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-8240 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-8240?

CVE-2026-8240 affects Concretecms Concrete Cms. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-8240?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-8240 have an EU (EUVD) identifier?

Yes. CVE-2026-8240 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31358.

When was CVE-2026-8240 published?

CVE-2026-8240 was published on 2026-05-21 and last updated on 2026-07-23.

CVE-2026-8240

CVE-2026-8240 is a medium-severity vulnerability in Concretecms Concrete Cms with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-284.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v4: 6.3
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31358
Weakness: CWE-284
Affected product: Concretecms Concrete Cms
Published: 2026-05-21
Last modified: 2026-07-23

Description

Concrete CMS 9.5.0 and below is vulnerable to unauthenticated page metadata disclosure across every page with a configured summary template, revealing the existence of private, draft, and restricted pages while leaking title, path, description, and author information. 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.

Frequently asked questions

What is CVE-2026-8240?: Concrete CMS 9.5.0 and below is vulnerable to unauthenticated page metadata disclosure across every page with a configured summary template, revealing the existence of private, draft, and restricted pages while leaking title, path, description, and author information. 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.
How severe is CVE-2026-8240?: CVE-2026-8240 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-8240 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-8240?: CVE-2026-8240 affects Concretecms Concrete Cms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-8240?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-8240 have an EU (EUVD) identifier?: Yes. CVE-2026-8240 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31358.
When was CVE-2026-8240 published?: CVE-2026-8240 was published on 2026-05-21 and last updated on 2026-07-23.

References

https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes

Affected products (1)

cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*

More vulnerabilities in Concretecms Concrete Cms

CVE-2023-48648 — Critical (CVSS 9.8): Concrete CMS before 8.5.13 and 9.x before 9.2.2 allows unauthorized access because directories can be created with…
CVE-2022-21829 — Critical (CVSS 9.8): Concrete CMS Versions 9.0.0 through 9.0.2 and 8.5.7 and below can download zip files over HTTP and execute code from…
CVE-2021-22958 — Critical (CVSS 9.8): A Server-Side Request Forgery vulnerability was found in concrete5 < 8.5.5 that allowed a decimal notation encoded IP…
CVE-2021-40098 — Critical (CVSS 9.8): An issue was discovered in Concrete CMS through 8.5.5. Path Traversal leading to RCE via external form by adding a…
CVE-2026-85385 — Critical (CVSS 9.6): Concrete CMS below 9.5.4 did not validate the user timezone value (uTimezone) on write and rendered it without output…
CVE-2022-30117 — Critical (CVSS 9.1): Concrete 8.5.7 and below as well as Concrete 9.0 through 9.0.2 allow traversal in /index.php/ccm/system/file/upload…

All CVEs affecting Concretecms Concrete Cms →

Other CWE-284 (Improper Access Control) vulnerabilities

CVE-2026-83944 — Critical (CVSS 10.0): Improper access control in Azure Logic Apps allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-20192 — Critical (CVSS 10.0): As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Identity Services Engine…
CVE-2026-87230 — Critical (CVSS 10.0): Vulnerability in the Oracle Hyperion Financial Management product of Oracle Hyperion (component: Security). The…
CVE-2026-54745 — Critical (CVSS 10.0): Kubeflow Pipelines enables users to build and deploy portable, scalable machine learning workflows. Prior to 2.17.0,…
CVE-2026-18886 — Critical (CVSS 10.0): ServiceNow has remediated an improper access control vulnerability that was identified in the ServiceNow AI platform.…
CVE-2026-76607 — Critical (CVSS 10.0): Joomla Extension - fabrikar.com - Missing ACL check in download element in Fabrik < 4.7.2.

Browse all CWE-284 (Improper Access Control) vulnerabilities →