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Vulnerabilities

Vulnerability · CVE-2026-3240

In Concrete CMS below version 9.4.8, a user with permission to edit a page with element Legacy form can perform a stored XSS attack towards high-privilege accounts via…

Published Mar 4, 2026 · catalog updated Jun 17, 2026 · concrete cms

Check if you run it

No confirmed exploitation is on record for CVE-2026-3240. EPSS is 0.28%. Act only if a listed version of concrete cms is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium4.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.28%
Remediation
Advisory link
Affected products
cpe concretecms/concrete cms

In Concrete CMS below version 9.4.8, a user with permission to edit a page with element Legacy form can perform a stored XSS attack towards high-privilege accounts via the Question field. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N Thanks minhnn42, namdi and quanlna2 from VCSLab-Viettel Cyber Security for reporting.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe concretecms/concrete cmsversion unspecified

How to fix CVE-2026-3240

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-3240. EPSS is 0.28%. Act only if a listed version of concrete cms is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 0.28%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 4, 2026 · NIST NVD

    Detected

    In Concrete CMS below version 9.4.8, a user with permission to edit a page with element Legacy form can perform a stored XSS attack towards high-privilege accounts via the Question field. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N Thanks minhnn42, namdi and quanlna2 from VCSLab-Viettel

  2. Jun 17, 2026 · NIST NVD

    Updated

    In Concrete CMS below version 9.4.8, a user with permission to edit a page with element Legacy form can perform a stored XSS attack towards high-privilege accounts via the Question field. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N Thanks minhnn42, namdi and quanlna2 from VCSLab-Viettel

Sources

  • CVE.orgVulnerability recordCVE-2026-3240

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-3240

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-3240

    In Concrete CMS below version 9.4.8, a user with permission to edit a page with element Legacy form can perform a stored XSS attack towards high-privilege accounts via the Question field. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.