PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-8433 Concrete CMS CVE debrief

CVE-2026-8433 is a low-severity CSRF issue affecting Concrete CMS 9 before 9.5.0. The vulnerable path is concrete/controllers/backend/file rescan(), and the vendor-assigned CVSS v4.0 score is 2.3 with a vector indicating network reachability, required user interaction, and limited integrity impact. The issue was publicly recorded on 2026-05-21, and the supplied corpus identifies Yonatan Drori (Tenzai) as the reporter.

Vendor
Concrete CMS
Product
Unknown
CVSS
LOW 2.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-21
Original CVE updated
2026-07-23
Advisory published
2026-05-21
Advisory updated
2026-07-23

Who should care

Concrete CMS 9 administrators, security owners, and developers maintaining deployments before 9.5.0 should review this issue, especially if backend admin functionality is exposed to regular users or if file-rescan workflows are part of operational processes.

Technical summary

The supplied NVD record describes a Cross-Site Request Forgery condition in Concrete CMS 9 before 9.5.0 at concrete/controllers/backend/file rescan(). The CVSS v4.0 vector is CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N, which aligns with a network-reachable flaw that requires user interaction and has limited integrity impact. NVD also lists CWE-352 and CWE-1275 as associated weakness classes.

Defensive priority

Low; patch during routine maintenance, but do not leave affected versions in place after an upgrade is available.

Recommended defensive actions

  • Upgrade Concrete CMS 9 to 9.5.0 or later.
  • Review backend access controls around file-rescan functionality and ensure only intended administrators can reach it.
  • Confirm that CSRF protections are enabled and functioning on custom integrations or overrides touching backend controller actions.
  • If you operate affected systems, verify the deployed version and plan remediation before the next routine maintenance window.

Evidence notes

All statements are derived from the supplied CVE description and the NVD modified record. The corpus states that Concrete CMS 9 before 9.5.0 is vulnerable to CSRF in concrete/controllers/backend/file rescan(), assigns CVSS v4.0 2.3, and lists the associated vector and weakness classes. The NVD reference list includes a Concrete CMS release-notes URL, but the supplied corpus does not provide additional vendor advisory text beyond the CVE description.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-8433 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-8433

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-8433 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-8433

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

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

    ff5b8ace-8b95-4078-9743-eac1ca5451de

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.